A sexual act which involves a split grapefruit with a hole cut in it. You then, while giving a blowjob, move the grapefruitup and down the shaft. This supposedly gives the male receiver more pleasure than a normal blowjob would.
When you have a grapefruit and you cut it into thirds, then proceed to cut a hole in the middle of it. After procede to suck your man's d*ck and get it hard. Then rub the grapefruitup and down. Remember grapefruit is a fat burner so you lose weight while sucking d*ck.
Using a grapefruit (cut at the sides) with a dick sized hole through the middle for sex. You put the grapefruiton the dick, and move it up and down while also sucking on the dick.