The first upgrade, and the easiest. Nothing new to learn. Start here if plain missionary has let you down before. One woman, 40, wrote on Reddit: "For 6 months, we have basically only done 1 position, me on top." They tried missionary once, it didn't work for them, and they went back to the usual.
What changes: her hips sit at 27° instead of sinking into the mattress, so the angle lines up without effort.
Where the pillow goes: under her hips and lower back.
For her and for him: her lower back rests on firm foam instead of arching. The lift brings her closer to him, so he isn't holding himself up on locked arms.
Slide into the next one: she lifts her legs. That's #2.

