This exists as a formal group with 1.1K members, and has some level of frequent activity, and is a private group with a couple of well educated administrators, guidelines, etc. Here was a recent post from a member with three questions, and my answers (which you are welcome to comment / discuss):
How often and for how long do you PM?
--1 to 3 times/week, varies from 15 minutes (in shower after cleaning 1st) to 1 hour lying down in front of mirror.
And for those who lead a busy life, do you or have you used massagers while you went about your business during the day?
--Tried this a couple of times: once around the house & outside by pool, once in the park where nudity is permitted.
What was the routine?
--Clean 1st, lube anus gently, prepare toy with lube for insertion, insert, pelvic floor exercise without vibration, attempt to “not touch” penis except for wiping drippage vs. otherwise sometimes