A blowjob, but performed with a mouth full of ice cubes. Proper technique is to take a large gulp including a few ice cubes of any cocktail on the rocks (Margarita, gin and tonic, vodka redbull, etc), drinking the liquid and retaining the ice in one's cheeks. If the ice melts before satisfactory completion of task, another large gulp of the cocktail is in order, only adding to the talent and skill of the performer.
Crushed ice is to be avoided at all times as it is not comfortable for either party and may lead to the choking chipmunk
You know, my girlfriend is pretty cool about going down on me, but this March 14th
she surprised me with a frozen chipmunk! She looked so cute down there with her cheeks full of ice. I was surprised not only with how good it felt, but also how quickly she had finished off both our drinks. We skipped the steaks and it turned into one hell of a night.