Late to the party here. As usual. Went through a D/s stage (I was the "s" most of the time). Got with a full time Domme, answers follow.
Questions for men who like pegging:
1. Do you prefer to be on your back with your legs spread or bent over doggy style? Did both, but bent over a padded sawhorse while chained to all four legs was probably the best. The feeling of hopeless helplessness to do anything but submit and surrender was exquisite.
2. Which position makes you feel more submissive (if you like D/s), and is that a turn-on for you? See the answer above to #1. Down on all fours, or bent over some kind of furniture and most importantly restrained is fantastic. The sexy, powerfully feminine woman taking me at my most vulnerable, some mild humiliation and corporal (spanking) just rounded out everything. I belonged there in delicious sub-space, this gorgeous, scantily clad woman railing me into next week. Oh, dear God it was good.
3. Do you like to see your partner while she is pegging you? If yes, do you like her to be clothed, in a bra, or naked? The sawhorse gal bent me over and had a mirror positioned so I could see her face down to her hips plowing me. She was wearing a fishnet body suit, ridiculous stripper heels and of course "her little (huge) friend" strapped to her loins. Powerful image I won't soon forget..
4. Do you like penile stimulation while you are being pegged? If yes, do you want your partner to give you a hand-job or would you prefer to masturbate? At "the end" a nice milking is great. Latex gloved hands slathered in lube, one around the gearshift, the other with two fingers up the joy highway pressing my buttons. I last about 30 seconds that way.