Not necessarily -- anal intercourse can transmit HIV just like vaginal sex. Your boyfriends should ALWAYS use condoms. Please!
Actually, it is just as safe and runs no greater risk of transmitting HIV than letting him ejaculate in your vaginal cavity. It may not run a greater risk than that but the point is you should always use a condom.
Depends on what it is and how you do it. Nothing too large or too deep. You can damage yourself fairly easily. Always with some sort of lubrication. It should be smooth and long enough so that you don't lose it inside. This would be embarrassing to have to explain to your mother.
It is not safe to put menthol in the anus.
It is safe to put yogurt in your anus.
No, it is not healthy.
The milk will not harm you, how you put it in may do so. There would be no benefit and silly to do it.
I'm guessing lots of practise!
Shops that sell toys have a variety of things for that. Go & browse or browse online.
Rectum? Probably not; the rectum is inside the body, and you probably couldn't get to it. The anus? The anus is the ring of muscle that is the exit from the rectum. If he/she maintains some basic hygiene and cleanliness, and isn't ill with ebola or cholera or dysentery, it's probably safe to do. Kinky, perhaps, but safe.
It actually depends on what you stick in the anus. The wall of the bowel is relatively thin and could be perforated (torn) if you put something sharp or pointy in there. That said smooth objects, carefully inserted, should be safe enough.
You just have to make sure it's safe.Do your homework.Toddlers chew on stuff and put things in their mouth so you have to make sure it's made of safe materials.
No. it is not.
No.
Yes, you can put clothes in your bum.