It seems that the distinction between drain and source is none. I noticed this when I was playing with a circuit and I noticed it seemed to behave identically both ways. I even took a couple of my circuits that included MOSFETs and flipped all the MOSFETs in them, and they both behaved no different than from before. Is this a bad implementation or are real MOSFETs actually like this (except for the body diode I’m hearing a lot about).
Edit: thx @hurz for pointing out my mistake. Yes I mean drain and source, not gate and source.