strength 1/1 seems to work fine.

I2V too, but also at much lower e.g. 0.5/0.1. So play around. I2v seems bad if they arent already in necessary position.

Example PROMPTs:

A woman sitting on the bed behind a naked man giving him a reacharound handjob from behind.

A woman sitting on the bed behind a standing man giving him a reacharound handjob from behind.

A woman sitting on the floor next to a standing man giving him a reacharound handjob from behind.