Read 50 Shades of Grey. They cover that quite well. Spanking should be done during sex/foreplay (at least, if both parties are interested). And what happened last night made me realize that it takes a lot of trust to do that, and not just that but both parties have to know their limits and expectations. There was more going on than what I wrote: I have very strong feelings for her that she does not know about, so I was also conflicted with how I felt and how I was supposed to feel. It was supposed to be a joke, but there were very confusing feelings for me and I was also scared not from her but from the action itself. And while that was happening I was also comparing myself to an erotic book and if it's suppose to be like that, too. Like Ana, she was a virgin like me and was afraid of spanking as punishment, but then she realized that she was turned on by the pain, and I thought well shouldn't I have felt the same way, even though it wasn't supposed to be sexual? It was just so confusing and I don't think I'm going to bring out the crop again unless it's for real spanking.