Green’s Dictionary of Slang

aardvark v.

[the animal’s image of ‘rooting around’ + ? a pun on ‘rooting about’ in dark places]

(US campus) to have sexual intercourse; thus aardvarking, sexual intercourse; one of many terms originating with animals.

Eble Campus Slang Apr.
[UK] Roger’s Profanisaurus 3 in Viz 98 Oct. 3: aardvark v. US To shag; bonk; go horizontal jogging.