The G-Force
The receiving partner's knees fold toward their chest while the kneeling partner holds their feet and lifts their hips. Intense, steep and all about the angle.
The receiving partner lies on their back and pulls their knees up toward their chest. The other partner kneels upright between their legs and takes hold of their ankles or the soles of their feet. Holding the feet, the kneeling partner lifts the receiving partner's hips off the bed so their weight rolls onto their upper back and shoulders, then rests their feet against the kneeling partner's chest. Unlike the Shoulder Stand, the legs stay bent and folded rather than straight, which keeps the receiving partner more compact and easier to hold. The receiving partner's arms reach out to the sides or overhead for balance, and the kneeling partner controls every bit of the movement by drawing the hips toward them. Lowering the hips a few inches toward the bed makes it gentler.
A strong angle toward the front wall of the vagina or the prostate, and a sense of being completely held and guided.
Keep the receiving partner's lower back on a firm pillow instead of lifting them fully. The kneeling partner can hold the thighs instead of the feet for more control.
The kneeling partner should check in often. The receiving partner can't move much, so words or a simple hand signal matter here.
Weight on the shoulders strains the neck, and the folded angle can go very deep. Keep the head straight, start shallow, and come down slowly at the first discomfort.
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.