Easy way to deflate rear air springs?

[Hit_Apex]

I recently lowered my truck and installed M5 bumpstops. These are shorter than the originals and want to verify that if a rear air bag fails while driving that the rear tire won't contact anywhere in the wheel well. Bumpstops are critically important for cars with self-leveling suspension for this reason.

Hoping for a quick and easy test without having to disconnect airlines.