The following information was taken directly from the Washington State legislation website at http://apps.leg.wa.gov/rcw/default.aspx

Unless the context clearly indicates otherwise, the definitions in this section apply throughout this chapter.

     (1) To "photograph" means to make a print, negative, slide, digital image,
motion picture, or videotape. A "photograph" means anything tangible or intangible produced by photographing.
     (2) "Visual or printed matter" means any photograph or other material that
contains a reproduction of a photograph.
     (3) "Sexually explicit conduct" means actual or simulated:
     (a) Sexual intercourse, including genital-genital, oral-genital, anal-genital, or oral-anal, whether between persons of the same or opposite sex or between humans and animals;
     (b) Penetration of the vagina or rectum by any object;
     (c) Masturbation;
     (d) Sadomasochistic abuse for the purpose of sexual stimulation of the viewer;
     (e) Exhibition of the genitals or unclothed pubic or rectal areas of any minor, or the unclothed breast of a female minor, for the purpose of sexual stimulation of the viewer;
     (f) Defecation or urination for the purpose of sexual stimulation of the viewer; and
     (g) Touching of a person’s clothed or unclothed genitals, pubic area, buttocks, or breast area for the purpose of sexual stimulation of the viewer.
     (4) "Minor" means any person under eighteen years of age.
     (5) "Live performance" means any play, show, skit, dance, or other exhibition performed or presented to or before an audience of one or more, with or without consideration.

RCW 9.68A.090Communication with minor for immoral purposes — Penalties.

(1) Except as provided in subsection (2) of this section, a person who communicates with a minor for immoral purposes, or a person who communicates with someone the person believes to be a minor for immoral purposes, is guilty of a gross misdemeanor.
(2) A person who communicates with a minor for immoral purposes is guilty of a class C felony punishable according to chapter 9A.20 RCW if the person has previously been convicted under this section or of a felony sexual offense under chapter  ,  9A.44 , or  9A.64 RCW or of any other felony sexual offense in this or any other state.

RCW 9A.44.030 Defenses to prosecution under this chapter.

(1) In any prosecution under this chapter in which lack of consent is based solely upon the victim’s mental incapacity or upon the victim’s being physically helpless, it is a defense which the defendant must prove by a preponderance of the evidence that at the time of the offense the defendant reasonably believed that the victim was not mentally incapacitated and/or physically helpless.
(2) In any prosecution under this chapter in which the offense or degree of the offense depends on the victim’s age, it is no defense that the perpetrator did not know the victim’s age, or that the perpetrator believed the victim to be older, as the case may be: PROVIDED, That it is a defense which the defendant must prove by a preponderance of the evidence that at the time of the offense the defendant reasonably believed the alleged victim to be the age identified in subsection (3) of this section based upon declarations as to age by the alleged victim.
(3) The defense afforded by subsection (2) of this section requires that for the following defendants, the reasonable belief be as indicated:
(a) For a defendant charged with rape of a child in the first degree, that the victim was at least twelve, or was less than twenty-four months younger than the defendant;
(b) For a defendant charged with rape of a child in the second degree, that the victim was at least fourteen, or was less than thirty-six months younger than the defendant;
(c) For a defendant charged with rape of a child in the third degree, that the victim was at least sixteen, or was less than forty-eight months younger than the defendant;
(d) For a defendant charged with sexual misconduct with a minor in the first degree, that the victim was at least eighteen, or was less than sixty months younger than the defendant;
(e) For a defendant charged with child molestation in the first degree, that the victim was at least twelve, or was less than thirty-six months younger than the defendant;
(f) For a defendant charged with child molestation in the second degree, that the victim was at least fourteen, or was less than thirty-six months younger than the defendant;
(g) For a defendant charged with child molestation in the third degree, that the victim was at least sixteen, or was less than thirty-six months younger than the defendant;
(h) For a defendant charged with sexual misconduct with a minor in the second degree, that the victim was at least eighteen, or was less than sixty months younger than the defendant.

RCW 9A.44.079Rape of a child in the third degree.

(1) A person is guilty of rape of a child in the third degree when the person has sexual intercourse with another who is at least fourteen years old but less than sixteen years old and not married to the perpetrator and the perpetrator is at least forty-eight months older than the victim.
(2) Rape of a child in the third degree is a class C felony.

RCW 9A.44.089Child molestation in the third degree.

(1) A person is guilty of child molestation in the third degree when the person has, or knowingly causes another person under the age of eighteen to have, sexual contact with another who is at least fourteen years old but less than sixteen years old and not married to the perpetrator and the perpetrator is at least forty-eight months older than the victim. (2) Child molestation in the third degree is a class C felony.

RCW 9A.44.093Sexual misconduct with a minor in the first degree.

(1) A person is guilty of sexual misconduct with a minor in the first degree when: (a) The person has, or knowingly causes another person under the age of eighteen to have, sexual intercourse with another person who is at least sixteen years old but less than eighteen years old and not married to the perpetrator, if the perpetrator is at least sixty months older than the victim, is in a significant relationship to the victim, and abuses a supervisory position within that relationship in order to engage in or cause another person under the age of eighteen to engage in sexual intercourse with the victim; (b) the person is a school employee who has, or knowingly causes another person under the age of eighteen to have, sexual intercourse with a registered student of the school who is at least sixteen years old and not married to the employee, if the employee is at least sixty months older than the student; or (c) the person is a foster parent who has, or knowingly causes another person under the age of eighteen to have, sexual intercourse with his or her foster child who is at least sixteen.
(2) Sexual misconduct with a minor in the first degree is a class C felony.
(3) For the purposes of this section, “school employee” means an employee of a common school defined in RCW 28A.150.020, or a grade kindergarten through twelve employee of a private school under chapter 28A.195 RCW, who is not enrolled as a student of the common school or private school.

RCW 9A.44.096 Sexual misconduct with a minor in the second degree.

(1) A person is guilty of sexual misconduct with a minor in the second degree
when:
(a) The person has, or knowingly causes another person under the age of eighteen to have, sexual contact with another person who is at least sixteen years old but less than eighteen years old and not married to the perpetrator,
if the perpetrator is at least sixty months older than the victim, is in a significant relationship to the victim, and abuses a supervisory position within that relationship in order to engage in or cause another person under the age of
eighteen to engage in sexual contact with the victim;
(b) the person is a school employee who has, or knowingly causes another person under the age of eighteen to have, sexual contact with a registered student of the school who is at least sixteen years old and not married to the employee, if the employee is at least sixty months older than the student; or
(c) the person is a foster parent who has, or knowingly causes another person under the age of eighteen to have,
sexual contact with his or her foster child who is at least sixteen.

(2) Sexual misconduct with a minor in the second degree is a gross misdemeanor.

(3) For the purposes of this section, "school employee" means an employee of a common school defined in RCW 28A.150.020, or a grade kindergarten through twelve employee of a private school under chapter 28A.195 RCW, who is not enrolled as a student of the common school or private school.