@WallCrawler3344 is your airsoft gun gas powered? or spring powered? I'm assuming it's gas powered because I don't know how a spring powered one could be incorporated to a webshooter (the switch). For gas powered, although I don't know exactly what yours looks like, what you wanna do is take apart the gun so you can obtain the circuit and the mechanism that opens the valve whether it being a mechanical push mechanism or a solenoid valve I'm not sure you would have to check. Then you could place the fluid cartridge where the valve fitting is where the mechanism pushes the switch or solenoid valve to open the cartridge valve. I imagine there is one part you would have to modify. When adding the CO2 cartridge to the back of the fluid cartridge, it would have to be separated by a solenoid valve so it only gets into contact with the fluid when you push the switch. Every time you push the button on the electric airsoft gun, a current will pass through to activate the switch. You could connect the wiring of the solenoid valve in parallel with the circuit so that everytime you push the button, the solenoid valve of the co2 cartridge will open as well as the mechanism opening the fluid cartridge. I hope that made sense.
@w3b-h3ad your welcome