holding pressure in pumping cylinder

I’ve been gone for awhile but…I’m back and glad I am. I have looked over and over this thread for the answer to my question but haven’t found the answer, so can someone please help? I’m in the process of making my own pump, but I’m going to start off, for the vacuum just sucking on the tube end. My question is, what can i use to clamp off or seal the rubber tube so it will hold pressure in the cylinder? Thanks for your help.

I fold the hose over on itself and apply a spring clamp to keep it kinked.

Use a inline flow control valve that way you can shut off the air after you pump up

Get an inline air pump ‘anti syphon valve’ from a pet store, $1-$2.