Re: The first one that caught me was just silly
When I was courting a young American girl (I was 15 at the time) the discussion turned to sex, and whether or not we should indulge. She said that her big siter allowed her BF to "Ride her Ass". As an Englishman in the US, I was highly amused to imagine the Big Sis sitting astride a donkey while her BF mounted it from behind. I shared this mental picture with my GF, and it took quite a lot of explaining that to us, an ass was a donkey and not an arse. (We didn't, by the way).
Biting the hand that feeds IT
