Why do straight men?

It feels amazing!

I only do it when I have a nasty roid and use a wet rag to scratch the hell out of it until it bleeds. The sensation and feeling of the scratching, way up there, even though I know it will hurt like hell for awhile, just feels so good. Could be a washrag, dishtowel, t-shirt..Anything that gets up there and does the job. Feels great while doing it. I had a roid happen while on the road for work one day, stopped at a mall bathroom, took the entire paper towel roll off the wall, formed pieces into a point, and stuck them up there to have at it. Drove home in intense pain, but didn't care.

I travel a lot driving from one city to another with my job. I always bring my toys along for hours of enjoyment in my private hotel rooms as I travel. I am pretty much a straight guy but love anal penetration and playing with my ass.
I like taking a long hot shower making sure that I am very clean inside and out and after wards I can spend hours when the mood strikes me playing with my fairly large collection of toys.
I have butt plugs rubber cocks of all sizes and quite a few with suction cups that let me fuck my ass hands free so I can play with my cock and balls and get off over and over. One of my favorites actually will shoot fake cum. It is a very thick 10" life like cock with huge balls and a suction cup base. Huge thick mushroom head that I can`t take unless I have used several toys earlier because the head is very large.
Once it slips in to my ass it feels very good going in and taking it balls deep will make me cum without even touching my cock. Cum pours out of my dick as it`s going up my ass and once I start to fuck my ass I cum even more then in the heat of the moment I like to shoot a few loads of fake cum in my ass.
It always reminds me of my big dicked friend back in High School that used to fuck me all the time and cum in my ass. Don`t knock it if you have never tried it.

OMG YES!!!

Hot

I know that's right

Well, there are nerves there, the prostate is there, and farther in an object puts pressure on the base of the penis. You notice how your asshole clenches up when you cum? It is all connected somehow. My ex wife used to play with my ass, mostly my butt cheeks when we fucked, and it seemed to always trip the trigger for me, getting me off quicker.
There are psychological reasons why too I guess. It has always been a little taboo, and anything you are not supposed to do is interesting. It is "dirty" or naughty.
So all that together I think contributes to it. If done right, it really feels good. A man can cum just from anal stimulation/penetration.

Prostrate stimulation gives for the best orgasms for men! It's totally normal.

I would think they would enjoy having a nice, hot cock in their ass. I think I might, too... once I got it out of my mouth.

Straight man here. I love sticking things in my ass and do it often. If you have never tried it you should. It feels great and if you have plenty of time to experiment you will find it is the best way to jack off and you will cum very hard with the right toy deep in your ass.
My wife loves to fuck me with a strap on and we both enjoy it quite often.