Term used by the YouTuber Duke Dennis when he does a great move on 2k and then makes the basket

Laughing At You.

Indeed.

Going on a hump spree.

This stands for: Laughing at you.
This is used in msn text.

Laying down as referred to in the past-tense.

Used by idiots in place of lieu of "lie" -- as in lying down, not telling an untruth. Confusion arises from the fact that the preterit of "lie" is "lay".

Infinitive: Lie (to lie down, intransitive)
Preterit: Lay
Past Participle: Lain

Infinitive: Lie (to tell an untruth, intransitive)
Preterit: Lied
Past Participle: Lied

Infinitive: Lay (transitive)
Preterit: Laid
Past Participle: Laid

The act of lieing down for sleep, sex, to eat food off your stomach while watching telly.