A friend or object that you keep close when you are nervous about a certain situation that frightens, or anytime there is a literal thunder storm.

when you're hungover as shit after a spending a night drunk as a skunk

noun: someone who is always there for you throughout a thunder storm to keep you safe from danger.

referenced in the hit movie "Ted"

A friend who comforts you when there is a thunderstorm as seen in Ted

Two people are thunder buddies when they have sexual intercourse under their blanket(s) during a loud thunderstorm, so that no one can hear there screams.

When your friend unknowingly traps you against a wall or hard surface while pressing their ass against your ass and farting. The essence of the succulent smell transfers to the cloths of the thunder buddy