Windshield fluid pump

I have a 2005 Envoy and everytime I press the switch to clean my windshield the pump connected to the windshield fluid reservoir pops out of place and it starts leaking. It also happens with the rear window pump. I tried pushing it down and putting back in place, that stops the leak. When I try to use it again, it works because I have fluid comming out to clean the windshield, but then it automatically pops out of place again!... How can i fix that?