One of my players runs a paladin who wears full plate. His name is Akari, but early in his adventuring career, when he tried crossing a water-filled chasm across a rope and ended up dangling half into the water, he was given the nickname "Tea-Bag."
This was only reinforced a few adventures later, when a completely different set of circumstances had him dangling from a rope into another body of water.
It got to the point where Akari named his pack horse "Tea-Bag," hoping to deflect the name, but we still call him "Tea-Bag" on occasion.
Johnathan
Our gnome monk wound up gaining the nickname "T-bag" after standing up while the human fighter stood over him...naked.