This has been a sometimes fun, but most often infuriating discussion between my wife and I, as well as other family members and friends whenever we bring it up: which side of the bed is the front? Is it the foot end? The side where the heads are? Or are you a rebel and is it the side you get out of bed at?
The reason you can’t agree is because it doesn’t make sense to describe any part of a bed/mattress as having a front.
So just stop using “front” entirely.
You have the top and bottom, head and foot, and both sides. There’s no need for a front or back.