(I know there may have been a couple of threads on this in the past. But they are closed. So I'm opening a new one.)
As a dude who wears diapers at every opportunity in order to relax, and as a dude who also LOVES massages to help him relax, I have in fact combined the two on several occasions, which makes for an amazing experience! The first full-body massage I had, in fact, was at a super-posh day spa/resort, and I wore only an Abena X-plus. I was scared to death and had no idea what to expect, I half expected the therapist to run out of the room screaming when she discovered my diaper. (I was too embarrassed to mention anything to her about it ahead of time) But, when she reached my diaper area, aside from a couple little pauses while I think she was trying to figure out how to tuck the sheet into my "waistband," never a word was said. The massage was spectacular and being diapered just enhanced the experience.
Since then, I have had at least a dozen massages, mostly with different therapists, and all while diapered. I did, however, in retrospect realize that it was a bit messed up that first time to not at least mention my diaper beforehand. So the next time (at a different spa) I mentioned to the therapist that I was wearing one. She just said "Oh yeah, it's no problem," and everything proceeded as normal. Each time thereafter I have given the therapist the courtesy of letting them know I'm wearing. Sofar I have only had one reaction to the news...the therapist asked if I had any concerns and I mentioned that I had a weak bladder (a little white lie), so I was wearing a diaper just in case. She laughed a little and said "Well that's always good..." Then she asked if I had to leave it on for the massage. I told her I would prefer to, it would help me relax. She giggled and shook her head a little and said "Diapers!" After that all was fine, it was a great massage and we chatted about world events and even politics, with no more mention of my diaper.
All in all, I have never had a negative experience wearing nothing but a diaper during a massage session, and the relaxing qualities of the massage combined with thick padding is a heavenly experience. (I usually wear a Dry 24/7 with a booster pad inside...I figure if something is worth doing, do it right!). I don't think most therapists really care one bit, although I do give them a heads-up so they have an opportunity to back out if it should make them uncomfortable for some reason. They are pros, and the diaper doesn't really get in the way of their job (well except for maybe the waistband which either you or they can easily fold down so they can access that lower lumbar region). Whether they joke about it later to their coworkers is debatable (they're human, I bet it makes their day!), but I always make sure to leave a great tip anyway, just in case, so I doubt they hate me too much.
So who else has experienced a professional massage while diapered? I guess my point of posting this is to put to rest any fears from anyone who may want to try it, but doesn't have the...intestinal fortitude? I am here to tell you there's no need to worry. You gotta try it, it's marvelous...even marvelouser than a "normal" massage!!