The act of inserting the cock into either the pussy or ass so that cock is so far inside that the nuts are literally sitting flush or slapping against the outside of said orifice...Sometimes predicated by the penis 'bottoming out' against the cervix. Should be a goal during any sexual intercourse....
Dude, the Platinum had his thundercock sunk to the nuts in this breezy's unsuspecting box!

Hey D-Pal, shut your pie, do you need me to be sunk to the nuts?
by Triple Platinum February 19, 2008
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