Threats and Manipulation

"If you don't do this to me, I'll find someone else who will", "You'd do it if you loved me"...  Forcing someone to do something that they don't want to do, whether giving or receiving, is to humiliate them and treat them like an object.  Love and respect mean accepting the other person's freedom of choice - when we feel free, we tend to want to feel even freer in bed, so there should be no problem in a loving relationship.