The easiest way is to use it heavily for several years. However, most of us don’t have several years on hands to idly lounge in bed and…uhh…watch Doctor Who for six hours a day.
One way that I just thought of using my coffee-addled brain is to take out a screw every night for about a week, so the bed gradually starts losing its sturdiness and then eventually collapses and comically injures the person(s) on it when it does.
Another rather humorous way of breaking a bed would be to create a black hole underneath it, thereby sucking the occupant and everyone they love into the black void of the unknown. But you can’t do that, because I wanna do that and I don’t know if the fabric of reality can take more than black hole at a time.