I thought it might be a good idea to write down the techniques people use in the "PE community". This whole thing was written as something off the top of my head, so feel free to add anything. Take this as more of a cautionary tale of what
not to do. This is simply for entertainment and discussion purposes.
Non-surgical methods:
1. Jelqing
The meme technique. Came into the public consciousness when big YouTube channels, like OneyPlays, started referring to it. However, by then, most people who were into penis enlargement were condemning it. Used to be a popular exercise, most likely, due to its similarity to masturbation, as well as the promised results.
Technique: squeezing the half-erect penis with an 'OK' grip from base to the glans.
Injury risk:
high
2. ADS/Extender
The only technique on this list with any kind of credibility attached: a research paper published on NCBI boasting its effectiveness. Has found use outside of intended use case, as treatment for Peyronie's disease (in combination with ultrasound therapy) and as aid in recovery after prostate cancer surgery. Initially equipped with a "noose", most modern devices have switched to the 'vacuum cap' design.
Techinque: wearing the extender in order to keep the penis fully stretched for, ideally, 8 hours a day.
Injury risk: ???
3. Vacuum pump

The most well-known device on the list, could be found in any sex shop since before you were born. Any results are temporary. People with Peyronie's disease should avoid using it for fear of trauma.
Technique: place the penis inside the cylinder and squeeze the pump slowly for 10 - 15 minutes (some people go for hours, though). Then place a cock ring at the base of the penis. Do not exceed 25 minutes with the cock ring on.
Injury risk: low, if all precautions are taken
4. Clamping
Technique: put a clamp at the base of the erect penis. Leave it for 15 minutes. You may edge while doing it.
Injury risk: ???
Injections:
1. Fat graft/Transfer/Lipofilling
Fat is taken from your abdomen or inner thigh with a syringe and injected into the penis. 30 - 40% of the fat is reabsorbed into the body within the first six months. The remaining result are said to last, with the addendum that you never work out. Presumably, because that way you risk burning the injected fat.
Injury risk: reported as low
2. Hyaluronic acid
An injection that increases girth. In the best case scenario it could last for around two years.
Injury risk: reported as low
3. Bellafill/PMMA
A kind of acrylic is injected into your penis. Your body's natural response is to create collagen around it, making the penis thicker. Is permanent.
Injury risk: ???
Surgical methods:
This part is what, I think, has not been discussed in the thread so far. Surgeries are often condemned in PE subreddits and forums for being extremely unsafe and not yielding satisfactory results most of the time. The injury risk with any of these is higher than with anything you could do yourself. Nonetheless, it somewhat relates to the topic at hand.
1. Penis extension/Ligament cutting
The ligament attaching the penis to the pubic bone is cut, exposing the "hidden" part of the member. Afterwards, you are required to wear an extender for six months. Following the procedure, your dick will never stand "straight out". The satisfaction rate doesn't seem to be high.
2. Penuma
Penuma is a silicon implant that gets surgically placed inside the penis to increase girth and length. Immediately after the procedure, scar tissue builds up where the incision was made, making the penis smaller. This is supposed to be counteracted by the expansion of the implant over time. A strong contender for the worst cosmetic penile procedure. The amount of associated problems is so high, removal posts take up 90% of discussion on r/Penuma. Has not one, but two subreddits created solely for removal stories. The rate of complications is close to 100%. These include protrusions, sharp pain from implant jabbing, suture breaks, irritation, numbness. If removed, the penis will be approximately 1-1.5" smaller than before Penuma was installed due to scar tissue buildup.



