Stoner sip
While stoned and mouth dry, you go for some liquid but there is very little remaining in the bottle and you know you will need it again. You take the smallest sip possible only to wet your throat while retaining enough liquid for many more stoner sips.
My buddy started coughing after a giant rip and asked for my water. I told him to take a stoner sip but the bastard finished off the rest of my water and we have a 9 mile hike to finish.