"Beer makes the dick go wonder"
Now then. Let's go through the series of events that led to this happening.
1) Someone decided to make a tshirt.
2) Someone suggested this slogan.
3) The slogan was approved.
4) The tshirt was mass produced.
5) A shop decided to sell the tshirt.
6) Someone decided to buy the tshirt.
And at no point in this sequence did anybody say "that makes no sense". Stockport is a strange place.