Sweat Memory

An old shirt that carries bacteria in the armpits causing your armpits to sweat more profusely than usual. The shirt will have visible signs of sweating under both armpits where the shirt has wet through due to sweating. The visible signs of sweaty armpits are nowhere near as severe when wearing a brand new shirt, this is because the shirt has no bacteria, or "Sweat Memory". You have previously sweated in that shirt and the shirt remembers it.

Man I have sweaty armpits today, its because my shirt has sweat memory.