Agree with others but would add “pump cover,” especially if it looks like they’ve been at it a while.

Lifters often wear a hoodie or an oversized shirt for their warmup sets. Once their muscles look slightly bigger (pumped) due to increased tone and circulation, off goes the pump cover.

This grand reveal is usually for the benefit of other lifters in the vicinity and isn’t necessarily sexual in nature.

Edit: not judging anyone. I do it too.