How to find RT groups?

I see that many adult pages and fake accounts are in RT groups. How can I find these groups and become a member?

Use Twitter's search to find rt groups that are relevant to you and accepting new members! For example, I usually search for bbw or 10k+ gif drop groups but there's also round groups and I use rt catch up groups on Telegram too. Right now I'm in 4 groups on Twitter (which I cu daily), 4 on Telegram, and then 10+ Twitter drop groups on Telegram.

as I know, just messaging girls and asking for rt groups work

There's a certain amount of follows you have to clear in order to be part of those RT groups. Hard to say who to get in contact to exactly to join them, save of course finding posts about it. Maybe try posting on the Joint Ventures section for these type of things?