When I pressurized my water system for the first time this year, just on last Thursday, I had a similar problem. Although my faucet is a Moen, the sprayer looks about the same. Where the trigger nozzle meets the shoulder of the hose flange, it was spraying out. Tightening did not help. Separating the sprayer nozzle from the hose, there did not seem to be any gasket. I thought about fitting a gasket or o-ring, but didn't have anything on hand to fit. I wanted to fix it that night, as we left the next morning for the weekend at Chain-O-Lakes State Park. I put a bead of clear silicone around the shoulder where the two parts meet, then screwed them together, tightened it down and let it dry overnight. Tested the next morning, and it's been fine.