I usually try to take my boys on at least a 2.5-3 mile walk every day. Now that it's getting hot--yes, it actually stopped raining in WA!--this is too far to go without giving them some water along the way. I bought a water bottle holder that you clip on your pants, but it's too heavy and drags down my pants--haha! Since I'm holding two leashes, I can't hold a water bottle as well. Is there anything on the market that would make a good, portable way to bring water along on the walks?