In New Mutants Vol. 1 #35 the boys change in their locker room, though only Cypher and Cannonball are shirtless.
And in New Mutants Vol. 1 #32 the team gathers for "a council of war" in their jammies... how cute! Once again Cypher & Cannonball are the only ones that are bare-chested. I love me some blond boys.