Stradlater comes back from the game and asks if he can borrow Holden's jacket. Then he hops in the shower to shave. He mentions that his date knows Holden and asks Holden to write his composition for him. But don't make it too good, he says. Make sure you put some commas in the wrong place.
Stradlater comes back from his date with Jane. He gets mad at Holden for writing about Allie's baseball mitt instead of a room or something.
Of course, he gets even angrier when Holden rips up the composition.
Stradlater refuses to tell Holden what happened on his date with Jane.
When Holden attacks him, Stradlater pins him down. It looks like he's trying to avoid a fight with an obviously weaker opponent, but he lets loose when Holden calls him a stupid moron.
After he gives Holden a bloody nose, he feels guilty. He tells Holden to go wash his face and then goes to bed.