Currently diving with a 7 mm farmer john suit that isn't the best fit. A little loose in upper body/ shoulders and have been freezing! Mostly beach dives in So Cal with surface temps in upper 50s. Anyway I'm seriously considering a semi dry suit but wondering how many people piss in their semi drys? Seems like a bad idea but so does holding it. In the meantime, thinking about wearing my 3 mil surf suit under my 7 mil. Has anyone tried this?