V2 UPDATE - improved consistency. Due to the nature of a low sample training database, different artists having different styles/tendencies and this being fetish content, the race of each penis is often random. It favors an interracial threesome (ie, 1 dark skinned male, 1 light skinned male). It will also struggle with making each penis different sizes if desired.

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This is a pretty competent model at making an internal cross section have two penises inside of the vagina.

This will require some fiddling with resolutions and poses and male colors to get exactly as you would like. This also tends to make the penises identically sized (low samples to pull from).