This is where you've mildly got the horn but you're tired/had a long day/been wanking all day anyway and then you force yourself to masturbate on top of all that.
Of course, consent is involved, it's not like you have to coerce yourself into grabbing your own genitals - "Oh come on, honey, you'll like it, I promise!" - more that you feel you should have a play, even given the state you're in, and you really try to enjoy yourself, but you heart's just not in it.
i spent two hours on my bully wank and all i got was this lousy orgasm and sleep deprivation.
This usually occurs when your partner, typically your girlfriend or wife, has gone to sleep and you have the horn but she is having none of it. To initiate the Bully Wank you gently push your hard-on into her back until she eventually gives in and she turns over and quickly and aggressively wanks you off.
She just wouldn't have sex with me, so she turned over and gave me a bully wank.