When I was going to the gym regularly I would pump full package using a wide mouth jar and some rubber tubing. I would shove the tube under my balls and stick my junk in the jar full of warm water. Then I would use my mouth to get to vacuum and jank the tube out. My gym shower had hair conditioner that worked perfectly as lube for the pump.
I would spend 10 mins pumping hard in the shower, then let off the pressure, put on my towel, and go to the sauna for 20-30 mins and repeat 2-3 times. I had a membership that let me go to any gym in the city so I would go to different gyms from time to time. I would also do a full freeweight / cardio work out. If I had hours to kill, I would pump before I left for the gym, get there and shower / pump for 10-15, then hit the weights for 45. Then I would go back to the showers and pump some more, sit in the sauna and drink water while pumped for 20 mins, then go back out to do cardio and drip sweat. after cardio I would go back to the showers and pump, stay pumped in the sauna, then go back to the shower, put on my cock rings, and go back to the sauna, this time being a bit of a show off.
I would put on tights / sweats or shorts with a jockstrap. I’ve even gone to fetish gyms and had fun with like minded people (and damn near died of heat stroke in the sauna). When I was using a bulb set up I accidentally dropped the bulb and hose, and it slid underneath the next stall. The guy kneeled down and presented himself understall when he handed it back and we ended up fooling around.
TL:D R tube and a hose. you can either bend the hose to hold the vacuum, jank the hose out entirely, or install a shut-off valve mid-way in the hose to hold pressure. Keep your supplies in one of those shower bags and whatever you do, don’t drop your tube! especially if it has a lip