The Ape
The bottom partner pulls their knees to their chest; the partner on top sits back onto them facing away, leaning back against their shins.
The bottom partner lies on their back and draws their knees up toward their chest, feet in the air. The partner on top straddles their hips facing away, toward the bottom partner's feet, and lowers down carefully, sitting back onto the backs of the bottom partner's thighs. They lean back so their back rests against the bottom partner's shins and feet, which hold them up, and they put their hands on the bottom partner's knees and their own feet flat on the bed in front of them. The partner on top moves by rocking forward and back with small hip movements; the bottom partner can push gently with their feet to help. Sitting more upright makes it shallower; leaning back fully deepens it.
Deep penetration with the partner on top in control, and a feeling of being cradled by the partner underneath.
The bottom partner can lower their feet to the bed and keep knees bent, so the partner on top leans back against their thighs instead.
Lower down very slowly and let the partner on top find the angle before any movement starts.
The angle bends a penis back more than usual. Keep movement small and controlled, and stop at the first twinge.
Agree on it before you try it, use plenty of lube, and either of you can stop at any point. This guide is general information, not medical advice.