Wtf, it's some kind of magical elixir you're supposed to dribble directly onto your dick 
Every detail about this ad is so fucking funny, from the roaring wolfman to the text.
AliExpress is a Wild West of shady medical products like these. Why does Elon Musk spend tens of thousands on hair plugs when he could buy a Chinese remedy that would give him a full mane of hair in a week for 10 bucks
There's fillers as mentioned.
Stuff that makes it look bigger too like cock rings or pumping.
Some trans femmes report enlargement when they use topical testosterone to prevent atrophy.
Also you can just buy like hollow strap ons that are pretty cool.