The rarely used and last resort tactic when its comes to icebreakers during conversations with females. A Nuclear Icebreaker is when you whip out your dick at the start of a conversation with a woman.
Defined by Pat from Two Best Friends Play - Youtube video "Cryostasis - Matt and Pats shitstorm of scariness" 12:43 minutes in.
Nuclear Icebreaker - When you are talking to a girl and you just take out your dick, because a normal icebreaker is weak.
When one opens, enters, or starts a conversation by pulling out their penis without hesitation to the other person or the whole group. (can also be an ice breaking ship that is nuclear powered)
Jefferson was drunk and walked up to sandy, pulling out his nuclear ice-breaker in front of her. She slapped him hard enough to knock him out cold on the floor. Jefferson then vomited on the floor.