First: you should practice SLOWLY inserting small diameter round things into your ass-hole using some lube like KY Jelly. Make absolutely sure these objects are CLEAN, and that they can't slip out of your grasp and disappear up into your ass! The Urgent Care folks tell stories about people who show-up with all sorts of things lost up inside their ass-holes.
As you get comfortable with, say 1/2-inch in diameter, get something a little larger. Work up to taking things in larger diameters until you can take at least 1-1/2 to 1-3/4 inches and you should be able to handle most average size cocks. These things only need to be long enough that maximum 6 or 7 inches max go inside you. But start with only a few inches initially.
Usually I have a little bit of pain upon the initial entry of a hard cock into my ass-hole as the head spreads my sphincter open, but with enough lube, and if he stops after the first inch or so, to let my ass get accustomed to the new invader, the pain goes away after a very short time. Once the pain is gone, it feels so erotic, sexy and naughty that my mind just kinda goes: "oh, yeah, fuck me with that cock!"
The whole idea in my head that here I am, letting a man slide his cock into my ass and fuck me as if I am a woman is overwhelmingly sexy. I only get to experience it maybe once every month or 2, which is not nearly enough to satisfy my horny hole!

Not only do I love to read erotic stories, I write them, too. Sometimes I masturbate while reading the stories I wrote.
Literotica is my favorite site for finding great stories others have written. Reading stories is better than watching porn, although I do love to watch porn, too!

Dark-skin guys fucking my mancunt until they blow their hot cumloads deep into me! I've managed to have this happen a number of times and am always hoping for the next time.

Also, feeling a cock (any color) squirt its cum into my mouth while my lips are sealed around the shaft. I always swallow!

I like to press my semi-erect cock against something stationary but not solid, like the end of an arm of the couch, pushing it and backing off over-and-over, letting the sensation build as I imagine I'm fucking someone, or a guy is behind me, fucking me in the ass. I can cum in less than 2 minutes this way, and never need to reach full-erection.
The best semi-erect experiences I've had with other guys' cocks are when I'm blowing a guy starting when his cock is still soft, then feeling it grow in my mouth.
Here's a series of pics I made of my cock as it grew erect.

I prefer smaller cocks for sucking because I can't deep-throat, so to get my nose to reach their pubes while blowing them it has to be 5-inches or less long. For taking in my ass I can't take more than 7-inches all-the-way, but I like them FAT so they stretch my mancunt wide-open. 2-to-2&1/4-inches wide feels SO GOOD in my ass!
My own is 6-inches long and 1.9-inches thick. I wish I could fuck my own ass! (I have dildos for that.)

My anus (see pic) often has a strong desire to be stretched open by a hard cock being pushed into it. So far 15 different guys have proceeded to thrust their cocks in-and-out until they came in me! Many others have fucked me but didn't cum, usually at adult video theaters.

Absolutely. When there's no real cock available, I have my toys!

I look at bulges, too. Here's mine in silk panties.

In my visits to male bath houses, adult video theaters, other guys homes for playtimes, etc., I have seen very few cocks longer than 6-inches (15 cm). The average seems to be more like 5.5-inches (14 cm). MANY are considerably shorter than that, which makes them great to give blow-jobs to.

The first time my cock entered a pussy there was one thing about it that was a disappointing surprise: almost all the pressure/friction sensation was on the sides of my cock, and almost nothing on the top and bottom of it.
All those many hundreds of masturbation experiences I'd had over the previous years (I started masturbating at a very early age) were always primarily focused on the top and bottom of my penis, not the sides. It took me a while to cum during that first fuck because my cock was not getting the kind of "attention" it was accustomed to.
Later I found that when she is on her side, and I'm in her in a "scissor" position, her cunt gives my cock the sensations I prefer. Anal also feels better, as the pressure around my cocks circumference is not as concentrated on the sides. When I can fuck an ass-hole with the receiver on his/her side, so the top and bottom of my cock are now massaged between their ass cheeks instead of by the front and back of their hole: that's the BEST!

If you walk around with no towel wrapped around your waist, and your cock is out in the open, that's pretty-much considered an invitation for others to touch it. Again, a simple hand gesture saying "no thanks" should be enough to stop unwanted advances.

At some places they have a "must wear a towel in public areas" rule, and in those places I've had guys reach into my towel to get to my cock. I don't stop 'em, 'cuz I'm there to play with other guys. I'm going to reciprocate and reach for theirs, too. Mutual fondling often leads to mutual blow-jobs, and often he will want my cock in his ass, which I am all for! Right there in the hallway if necessary!

No one who knows me knows I love to suck cock (& swallow cum), and that I love to have anal sex with other men.
I take cocks into my ass until they pump their cum into me and I give the same. Occasionally a FB will paddle my bare butt for being such a bad boy.

While at the sauna and walking around, standing or sitting naked, playing with your cock in the open, you can indicate with a simple hand gesture to any guys who approach whether or not you welcome their attention. Your cocks size really won't matter, so long as it's not a micro-penis.
Even if you are 100% straight, a BJ from a guy is still enjoyable. Just close your eyes and imagine it's your dream movie star on her knees blowing you. The guy doing you will certainly enjoy himself, especially if you blow your load in his mouth, as that's what he's hoping for.