This is by Bob Dvorak. It was posted on the groaners listserv.

Engineers at the Playtex factory had been hard at work developing a new brassiere targeted for sizes DD and up.

The problem they faced was in the straps –when the rear hooks were released, the forward shift in mass was almost earthquake-like in the stress it placed on the straps.

So they’d go next door to their favorite bar for a round of Playtex Tonics.