Section 17. Persons within degrees of consanguinity within which marriages are prohibited or declared by law to be incestuous and void, who intermarry or have sexual intercourse with each other, or who engage in sexual activities with each other, including but not limited to, oral or anal intercourse, fellatio, cunnilingus, or other penetration of a part of a person's body, or insertion of an object into the genital or anal opening of another person's body, or the manual manipulation of the genitalia of another person's body, shall be punished by imprisonment in the state prison for not more than 20 years or in the house of correction for not more than 21/2 years.