For several years I have used a variety of anal stimulation when masturbating, solo, with my wife and on a rare occasion with another male. I started with finger insertion as a teen. As an adult I have bought several dildos for use in mutual masturbation with my wife. She does not masturbate with me or infront of me, but she has done solo. I frequently masturbate solo. I made a video, using a tripod, of me masturbating, using a dildo in my anus. It started with a close-up of me fingering and lubing my asshole, then fucking myself in the asshole with a medium sized flexible cock-like dildo. I then changed the camera to show me jacking-off while fucking my asshole with the dildo, finishing with a cum shot.
I watch this video sometimes when I jack-off. One night, we were getting ready for sex and I put on the video. Watching it she said she knew that I masturbated (I had cum in the toilet and forgot to flush) and that seeing it was a turn-on for her. While we were watching I was fingering her clit and she was slowly working her hand on my cock. When we had settled down, she got the dildo and lube out of the drawer. My heart was thumping! In the video I had been on my chest and knees, so I got in that position. She squirted some lube in my asscrack and started to massage my asshole with her fingers, I just about came right then! The dildo is about 8'X2', I had used it once on her, but she didn't like it and had asked why I didn't throw it away (now she knew). She said 'it's awefully big', I just pushed my anus against her fingers and told her to go very slow putting it in me. Next I felt the big dildo head against my asshole, with slow, steady pressure it slipped in and I let out a pleasure groan. She asked me 'is it OK?' I said 'fuck yes, now fuck me'. She began to slowly fuck my asshole and after about 2 minutes of me jacking-off I had the most intense orgasm I had ever had up to that time.