Having sex with a young lady on the floor of an icy cave. This kind of intercourse is normally restricted to caveman times; when it was common to copulate on the floor of an icy cave with the local snickers. In more recent, albeit contemporary usage it simply means 'getting laid'.
Sandro: "So how was that date last night Danny?"
Danny: "Icy cave ream basically boys!"
by llamaplex November 2, 2006
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