286. (a) Sodomy is sexual conduct consisting of contact between the penis of one person and the anus of another person. Any sexual penetration, however slight, is sufficient to complete the crime of sodomy.
It goes on with an extensive list of specifics, e.g.
(b) (1) Except as provided in Section 288, any person who participates in an act of sodomy with another person who is under 18 years of age shall be punished by imprisonment in the state prison, or in a county jail for not more than one year. (2) Except as provided in Section 288, any person over the age of 21 years who participates in an act of sodomy with another person who is under 16 years of age shall be guilty of a felony.
This will take you to search results on "sodomy" in the California Penal Code: http://www.leginfo.ca.gov/cgi-bin/calawquery?codesection=pen&codebody=sodomy&hits=20