Feeling a firm penetration of my anus gets me off big time.
Sometimes I really like anal stimulation when I masturbate. Lately it seems like it can create a more "complete" orgasm for me. I like to get on the floor on my hands and knees and reach around and stimulate my ass with lubed fingers and usually toys too. One of my favorites is a soft rubber butt plug thing. It has a flared base and several gentle ripples on it. Sometimes I put it on a box and squat over it, riding up and down on it. It's awkward when I reach around and work that thing in and out and I've often thought of a way to make that easier.
So today I got a few bricks and a narrow board. I put 2 bricks stacked up on the floor then the board on them to make like a lever. I put the butt plug on board and worked into my ass. Then I held the other end of the board and moved it up and down. It used the bricks as the fulcrum so that when I pushed down on the board, the plug went up into my ass. I could adjust the angles of my butt and the board to try different things. I think the best thing about it was that I could relax my legs a bit more due to not having to reach around with one arm. So I worked it slow at first then faster so that thing was sliding so smoothly in and out of my anus. It was easy to vary the depth and speed. Finally I started stroking my dick which had already dripped quite a bit of cum. The orgasm was one of the best I've had in recent times.