The most wonderful of happenings, an event, action, or thing that causes everyone in the room to shudder with pleasure in response to the glory of the occurrence. In other words: you find your genitals involuntary soaking your thighs because of your excitement.
Ken: dude, Mary's wearing a tank top
Atticus: oh, that's a thigh drencher *fist bump*
Julie: hey remember that day we watched O Brother Where Art Thou? AND Blazing Saddles on the same day?
Allison: Oh my god yes, that was such a thigh drencher
Paul: dude wanna get some pizza and slurpees?
David: damn, that sounds thigh drenchingly awesome right now
Matt: oh god... my socks are soaked
A small piece of information. Derived from the word ken, used often in the scottish language and is synonymous with knowledge.
Person 1: "Hey I don't get this shit. How do you solve this problem?"
Person 2: "I got that one. Give me some kenlets on this assignment and I'll help you w/ that one."