I got my Big Boy today and was very eager to try it. The diameter wasn't more than what I'm used to already but it is true, this is very hard to keep in. I tried inserting it from the front and there was no chance of getting that third ball in. I could do it from the rear but when I turned it around to the front it was shoved back out. It's just the way my body is shaped, it won't fit. Like the reviewer did, I had to sit on it to keep it in. This was my first time using a prostate massager and I have to say it did little for me. I felt the vibration but I couldn't feel it in any spot that did anything for me. And for five hours afterwards it felt like I had been kicked in the nuts. I was an aching unit. After this experiance I don't think massaging the prostate is for me.