Would you ever wear a decorative butt plug while getting massaged so that the massager could see it and maybe ask about and go a step further. Like an Ics breaker.
You don't need to wear anything of a sexual nature when getting a massage either from a licensed therapist who wouldn't make any sexual advances or a masseuse where sex is expected. The therapist could halt the session in the event they actually see the plug. Many keep your body totally covered except for the area they are working. Very few massage the glutes much less expose them to where the plug would become visible. A masseuse such as in an Asian Massage Parlor or an independent massage provider doesn't need an ice breaker that is as prominent as a butt plug to know you would enjoy a happy ending. They don't care how you adorn yourself. Only how much they can make from the massage.
I’m an LMT. There’s no way I’d know if someone was plugged. Heck, I don’t even know when the diapers are kink or medical. As a Medical massage therapist, I’d end a session, charging full price (no discounts) and likely report the offender to police for attempted sexual assault. It’s codified where I live.