undercover lingerieMens Undercover Interlock 100% Cotton Y Fronts Briefs Underwear Blue or White Small-5XL (6 Pack)

Are these high waisted.

are these fly opening or not.

I'm a 36 inch waist. what size should i buy? l or m?

I ordered 3xl for the size he said 46x48 anyone any clue which size he thinks large i dont want to be ordfering and sending back not good for the sell