The thought that will make you nut. Oftentimes porn is insufficient and you have to fantasise about other women to ejaculate. Said fantasy is the nought.
Damn, I had a really good nought yesterday but I lost it. Should have avoided porn so that I could've concentrated on the nought
The phrase used to judge how sexually aroused you were, or how sexually aroused someone would make you.
The phrase plays on 0 - 60mph, with "Semi" being a half erect penis