Most I've found so far is when you have girls over during a House Party and the Blackjack Party Game triggers. Then it's a matter of hoping the women will agree to forfeits and you'll be the recipient (or participant) of either a makeout or cunnilingus.
Otherwise, I haven't seen anything.
I did recently find extra Lowlife content that triggered randomly. You run into the lowlives a second time while hanging out with a female friend (mine was innocent sales-colleague who was encouraged to stay and have sex to de-stress) and if you have 'Shy' and 'Weak-willed', you can get it on with them in an alleyway.