Someone who meets two requirements. Firstly, being exceedingly attractive, and secondly being exceedingly cool. Someone who is a hotsicle, typically has lots of friends who admire him/her (or alternately are envious of him/her). Any guy or girl in a relationship with a hotsicle tends towards being very lucky in the short term, but runs a risk of being extremely unlucky in the long term, as hotsicles also generally are not the brightest people around, and lack key principles where relationships are concerned.
Guy 1: Man... Did you just see that girl that walked past us? I'd hit that in a new york minute.
Guy 2: Are you kidding? I agree she's a hotsicle, but you know what they say about those...