I once had a blowjob I didn't want. So I elaborated, and she said "Whats the matter, you don't like blowjobs?", and since I'm a man with alpha-male tendencies, anti-faggot agendas and all that, I was like fuck it, suck it then.
HAH.. No like blowjob?
My theory is that the guy was insecure and did not want to reveal his shriveled mushroom cloud dick. And as the brain was taking a time out sleeping and could not spout the usual "you are worthless, you disgust me, you smell like piss etc" soundtracks for eroticism, the penis (I call mine the hellhound, or the octagon) miraculously got erect and the situation escalated into this huuuuuge pile of perplexity.