Bottoms who have topped: what was the first time like?

The first and only time I ever did it was pretty awful. I had a growing relationship with a guy (we were hooking up when we hung out). Long story short he wanted me to top him and I was willing to try but when it came down to it, I wasnt turned on at all and couldnt get hard. The guy basically forced my flaccid dick in his ass and i had to think of some other sexy time i had in the past. I came really fast but I wasnt upset because all I wanted was it to be over as soon as possible. I dont remember if i said anything but I left his apartment immediately. I felt like I was sexually assaulted even though I was the one topping i never saw the guy again