Most of modern American Christianity is pretty relaxed about what heterosexual married folk do in the privacy of their bedroom. I don't think there are enough people into scat that it's an issue very often.
I was mostly responding to Isabel, but my understanding is that officially you aren't even supposed to kiss on the lips before marriage. What is acceptable is obviously going to differ a bit from church to church and family to family.
Chastising people for having natural feelings is undeniably unnatural. I don't see anything particularly noble in the atypical Christian understanding of sexual relationships and marital relations. In actual fact I consider it a huge pile of bollocks.
Believing that any God would want his creation to avoid the most primal of acts that we have, is insane. You'd think any God would want his creation to enjoy themselves, no?