What did Abbott and Costello do in that bedroom they shared?

Sleep I hope!!!

Worked on new gags probably.

Sat up in bed all night eating pickled onions and watched old movies

argued over whether  you should eat a hot dog with ketchup or mustard. 

Are you trying to put the mustard people out of business? 

Who knows there's lots of men that share a bedroom in the recovery halfway house there's 40 men and 20 rooms every Man has a male roommate. 

That doesn't necessarily mean that it's a house full of gay people. 

I would assume they slept.

They did not share a bedroom. They were both married to women.