The seal is the bit that you push against your skin, the opening. If you put vaseline around the foam rim thing, it will get a better seal when you pump the water out.
If no water is coming out the end when you're pumping down, you may have too much air inside the [words=https://officialhydromaxpump.com/?uid=6&oid=2&affid=98 ]Bathmate[/words] (ie. their is air coming in the opening because you haven't got a tight seal) or you've reached maximum pumping capacity... But I think you'd know if you were at maximum, your dick would be screaming at you.
Otherwise if you're super unlucky like I am, you may have ran over your [words=https://officialhydromaxpump.com/?uid=6&oid=2&affid=98 ]Bathmate[/words] in your car when the postman decided it'd be a good idea to put the package under your tire and now you have a crack down the side that is leaking air in. Lucky I was cashed up at the time, got a new one.