I'm a guy who produces streams of precum from the time I get hard until I shoot off. It didn't matter what type or size of condom I tried, they all slipped. I got tired of holding the ring on while I was screwing. I found a product called "It Stays". It is a medical adhesive and is latex safe. I got the type with a roll-on applicator. As soon as I was hard I used it to apply the stuff from about 1/2 inch from the head back to the base and unrolled my condom down. That rubber sealed instantaneously to my dick. Needless to say my problem was solved and I test drove it in numerous positions. Wow - no leaks and no worries. After I came I peeled it off easily. It cleans up fast with water. I found out it is also hypoallergenic. It has to be a safe product since it is used every day by people to apply things like artificial breasts, latex makeup pieces ,etc. Hope this hint helps some of you guys with a fountain like mine.