A bean seal is a person who wears a hoodie with a tight hood, thus making the person look like a bean or a seal. The hood may also be pulled tight on a looser hood to produce the same effect.
To bean seal or 'pulling a bean seal' can also be used as a verb.
Bean sealing is the practice of wearing a hoodie with a tight hood.
e.g. Friend 1: "Aw mate! My hair look terrible today" Friend 2: "Looks like you're gonna have to bean seal!"