For frontals of erect men.

LoRa strength 1 - 0.55, try something in the middle as a start

Flux works well with full sentences, use a combination of detailed sentences and tags.

Penis is the style tag, then use, "a naked man"(this is an important tag), prompt, "erection" or "penis" if needed

I've found that this model will forget where penises go. "uncensored" or, "penis between legs" seems to cure this.

Can do dismembered images of penises. Use this to your advantage.

Foreskin prompt exists but doesn't fucking work I guess

https://civitai.com/models/721126/erect-man-flux-dev-cruzflesh