instruct-pix2pix works great mixed 50-50 with URPMv1.2 and a prompt of just:

(cum on face, cum string:1.4) <lora:cumshot_49:1.0>

No masking, nothing. Instant cumshot for img2img!

Denoising strength of about 0.37 is a good balance, can lower denoising and raise prompt weights a little to try and keep more original face detail.