There's a stigma against it because a lot of people are scared of their own rectums. Ultimately, it's a matter of personal preference; if you're adventurous, try it- it works great. If not, there's plenty of other methods that don't make you feel violated.
You can plug pretty much anything except weed and DXM- but always Google it first, just in case.
Shit, my face is broken out for my big hook up with Alan. I hope he knows I'm plugging.
'Plugging my girlfriend was so amazing last night, I just went to her viewing.'