Haven't done one of these in a while. It's a straight copy of a pose from Charlton comics's Atomic Mouse #28, cover date November 1958. You can see the original at page 32 of https://comicbookplus.com/?dlid=82459 as part of the story ``Out of Shape''.

Why am I doing this? Because I'm tired of how much I suck at drawing mice, and there's no cure for that except drawing some mice, and Atomic Mouse has got a bunch of mice with at least some variations in exact model and pose and everything, even if it is from the era when people would exercise while wearing bow ties for some reason.

Original artist not credited. The front cover is very much copying Tom and Jerry though. Give that a look sometime.