I'm a straight teenage male, but I can't climax unless I am stimulating my anus or rectum. I use various objects like cucumbers. The reason I don't buy a toy is that I live in a very religious household and my parents would disown me if they found a sex toy in my room.
I take a toilet plunger and wrap the handle with toilet paper and tissues. Then I take a plastic bag and put it over the top. After that, I wrap a rubber band around the bottom part of the bag so it can't slide off, lube it up, and fuck away! I really like this: I can put the suction part on the floor, sit on the handle part, and basically ride it while I use my hands to stroke my dick/balls.
I know you're thinking, "Gross! Do you realize that thing's been in the toilet?!" But I sterilize the handle with Lysol, then put soap on it before wrapping it with toilet paper. I also put disinfectant on the plastic bag, then wash it off with water. After I'm done, I put more disinfectant/soap on the handle and wash it off so people who are using the plunger for its normal use don't get my ass germs. I've been doing this for about five years and haven't felt any bad symptoms except the occasional trace bleeding (I think due to not enough lube—or it may be due to the ridges of the bag). A few times I actually bled a lot (about the same amount as a medium cut on your finger) for two or three days, but I didn't feel it in my butt and only knew that I was bleeding when I took a shit.
Are homemade dildos a bad idea? Am I putting my family at risk by getting my ass germs on the plunger?
Always Nervous Until Sanitized
For the love of God, ANUS, get your hands and ass on an actual sex toy—they make dildos with suction-cup bases—before you do some real damage to yourself. Your 10-step toilet-plunger-into-anal-sex-toy plan is ingenious, I'll admit, and your concern for the health of your family is touching. But given a choice between explaining your masturbatory routine to your parents because they found a dildo in your room or explaining it to them because you wound up in an emergency room because your luck ran out and the bleeding didn't stop, ANUS, I hope you would opt for the former.
If you're worried about the repercussions of discovery—such as being disowned—then hide the dildo someplace other than your room. Got siblings? Hide your dildo in the room of your least favorite. If you're an only child, find a beat-up-looking box, a couple of porn magazines that predate your family's tenure in your home, and hide the box with the dildo and old mags in the crawl space or a drop ceiling or the rafters. If your folks find it, they'll think it belonged to some perverted previous owner or tenant, not to their straight-but-needs-anal-stimulation-to-climax son.
A word to my fellow parents: If you find a penetration toy hidden in your child's room—why were you snooping?—do not freak the fuck out, do not disown your kid, and do not discard the toy. Your child probably went to great lengths to obtain that toy—teenagers can't just walk into sex shops—and he or she probably didn't decide to run the risks of obtaining and concealing a sex toy until he or she had a bad experience with an improvised sex toy, e.g., plunger-related rectal bleeding, difficulty retrieving a cucumber from the vaginal canal. If you make a scene and take the toy, your child may not acquire another—but your child's experiments with insertion will continue. He or she will just go back to using produce (swiped from the fridge for use, then returned to the fridge after use) or plunger handles or worse.