Bubble gum? Like do they chew space bubble gum that they could then smoosh in the holes?

In college, we'd use toothpaste for the holes left from nails in the walls we hung up our posters with.

They did use space tape (Kapton) and epoxy for that weird case with the hole drilled in the ISS.

Duct Tape, the answer is always duct tape

can't one of them just put his thumb in the hole? duhhh