When a two people kiss cuddle & fuck during the late night and early morning hours of the day.
Craig : So why were you late for work again today?
Chad: I was over at Kiersten's again and we went "All Night Long" and my dick was tired this morning!
Craig : Nice!!!
Said first by Karl Pilkington- a fantastic idiot with a head like an orange- in conversation on The Ricky Gervais Show podcast about 'I'm a celebrity get me out of here' and a celebrity eating a kangaroo penis.
Ricky: "So what're you saying??"
Karl: "I'm saying...I could eat a knob at night."
To have commitments the next day, esp. in the morning, eg interviews, work, dates etc, that prevents you from doing something (usually fun and stupid) on that night.
Originated, (obviously) when having to go to bed early because school was the next day.