A complete knob jockeying
slut, be they male or female. So obsessed with penises, that they don't even notice the guy attached to it. Every workplace, town and secondary school has one of these "knobsessed" individuals. Teenagers and middle aged guys often fall victim to the knobsessed. You can recognise them by their trousers (which are too tight) and their hair (which is too bleached/dyed/straightened/backcombed) and by their voice (which is too loud).
Ed- "Look at Tracey chatting up Darren"
Meg- "Ewww, he's a freak of nature!"
Ed- "I know, the girl is totally knobsessed"
"Donna didn't recognise me in town, even though we shagged last week. I think she was just knobsessed with me"