Consent is not always part of the issue of abuse. Consent may be given for an activity because the sub so loves her Master that she will give consent to make him happy, but just becasue consent is given does not mean the act should still occur.

I know this sounds a bit wanky but I really believe the dictionary terminology is the best: to use wrongly or improperly. If you know that your actions will hurt the other person in your relationship and you still continue for totally selfish reasons or you simply don't care for that person - that is abuse. It can still be consensual but having consent does not make it right. There are some people in this lifestyle who are so desperate to be loved that they will do anything to have those feelings. To use that frailty and need to your own advantage is true abuse.

Jason