What is California Penal Code 288 Lascivious Actions with a Person Under 18 Years of Age? It is a sex offense in California to engage in a lascivious act with a child.  Generally, a lascivious act with a child is either having physical contact with a child for the purpose of sexual gratification or pleasure.  It is also compelling a child to physically contact either themself or another person for the purpose of sexual gratification or pleasure.  This sex offense is codified in the law books as California Penal Code 288 Lascivious Actions with a Person Under 18 Years of Age