A picture of my pants, in my pants...in my pants...in my pants...
(Like those pictures of pictures that go on for infinity.)
Jacob Black in my pants. (But no shirt.) (Sheesh, does that guy even know the meaning of the word "shirt?" You think he'd have learned it from Edward Cullen during one of the previous times that they had sex.) (I love insulting the Twilight series.)
The actual actor hates to take his shirt off, so yeah...he's just playing a part. Werewolves (in that particular book saga) have really high body temperatures so having a shirt on (even if it's just a t-shirt) isn't comfortable for them. Be glad that they all still wear shorts. lol.