Even though both were fully clothed, he got on top of his girlfriend and engaged in frottage with her by grinding and gyrating his crotch on her till he ejaculated in his pants.
To mention some favor you did or gift you gave to the recipient, in the hopes of receiving a compliment, usually long after the fact.
Tobias (who last week fixed your bike): Those new rims are looking pretty sweet.
John: Yeah, but please ease up on the frottage. I can practically smell your cock.