[Itty-bitty]

Thanks Karren. Sounds helpful. I don't know what you mean by 'air valve'. Can you post a link and/or picture? Is this the same as the air lock from Noogleberry*? I considered putting duct tape over all places where hoses connect to the domes, to other hoses etc. Would that be helpful or it is only the hand pump that leaks pressure? Also, would a bulb shaped pump leak pressure as well or not? Do you think this airlock from Noogleberry would work instead of the air valve you talk about?

PS: the skin glue was very hard to remove. Better to use vaseline. I made the Brava top narrower (2cm on each side, so 8cm in total), this helps with getting a seal. Once I have pumped they stay stuck to my skin now, even when they lose pressure. So I didn't get how they could still lose pressure, it makes sense that air is leaking from somewhere else!
PS2 @fozzie: I lose pressure even when lying still on my back. My chest can still move because of breathing, but that's it. An yeah it sucks that they're out of business and the similar domes (forgot the name) are only for sale if you get lipofilling surgery with a specific surgeon in the US. You might be able to make something yourself though with gel cushion material? It's sold in sheets sometimes.

*https://www.noogleberry.com/products/airlocks?_pos=1&_sid=526946a3c&_ss=r