Timejack 

The act of telling someone, who is perpetually late, that something starts sooner than it actually does so they will be on time.

Boss: Will Katie be on time for our 11am meeting?
Employee: Yeah. I totally timejacked her. I told her it was at 10:30.

Timejack by catlady82 May 17, 2015

tiejack 

To pull down the wider part of somebody's tie to create a stiff knot at the top which is almost impossible to undo. Most commonly used as a prank in British schools where ties (long narrow piece of fabric tied worn around the neck and tied with a loose-ish knot) are usually part of the uniform.

Random Student: Got tiejacked 5 times today. Now I can't get my tie off.

tiejack by Luna lovegood December 16, 2014

Sexy-time jack-off 

When an individual, usually a guy, will get soooo into a masturbation session that they'll get completely naked, touch their bunghole, and even rub their own nipples. They might even have sex with a couple of pillows or cushions to simulate a real sex experience.

"Dude, I'm going to go and jack-off. Wait, I think I'm due for a sexy-time jack-off. I'm excited!"

Sexy-time jack-off by Andy22P February 7, 2008