This sounds disturbingly like a Harry/Ginny first time fanfic written by a die-hard Snarry fan (because Snape had obviously given Harry some hardcore mind-altering potions beforehand).

This bad sex scenes thing went around the f-list last year or before, and what I noticed was that it didn't differentiate between intended-to-be-good-bad sex scenes and intended-to-be-bad-bad sex scenes. Although, it is hard to decide which one the above quoted was supposed to be. It is even horrible at being horrible.