A colorful euphemism for inserting the penis into an orifice. This of course makes ready sense; anyone who has studied American music can tell you that when you sing the blues, meat products are male, and bread products are female, with the exception of occasional entertainers who referred to themselves as "Jelly Roll".

This is usually either prefixed with "slip her the" or, for those who are inclined towards pseudo-medical terminology, "administer the".