This is Frank and John from Michael Rosen's book Sexual Art available at Amazon. - Image by Michael Rosen
Here are all the facts, experiences, techniques and media/links we have on:

Bottom

A bottom can refer to the one's bum... Or to a submissive. 

It's possible when someone says they are going to spank your bottom that they want to take you over their knee... Or it could mean they are talking about your submissive, and it's your bottom (ie. your submissive) whom they want to spank... Get the distinction?