Any 24 Oz can of beer, usually domestic, not to be confused with a "tall boy", a 16 oz can of beer. A man can is bigger in both diameter and height, and a tall boy is the diameter of a normal 12 oz can but taller.
Used to express the idea that white men can't jump as high as black men can on the basketball court. Also used to express the stereotype that white men can't play basketball that good.
White man: "Come on man! Let's go outside and play some basketball!"
Black man: "Bruh you know white men can't jump"