I almost didn't read this because I avoid het like the plague, but considering the author and the prompt... I love how Remus was capable of having sex with Tonks, but only by concentrating on past lovers.
I'm not quite clear on how having sex with Snape in the hall closet lead to doing it with Tonks.
Teddy's father is a Death Eater?! That's one I hadn't thought of before. Bad sex followed by a very awkward proposal - only someone with a heart like Remus would agree to marry her.