Vacuum enlargement or penis pumping is the practice of sticking you manhood into a device. Applying air pressure to create a suction which then draws blood flow and body fluids into your private area. Forcing the spongey chambers and blood vessels in you cock to forcibly expand. Resulting in pleasurable feelings and large temporary and sometimes permanent size increases. I am going to describe one of my typical sessions.
I keep all of my acrylic vacuum tubes together in a central location. I use a step progression beginning with my 2 in diameter tube and working my way up and up. I drink plenty of fluids daily. I always try to pee first before I begin. I gently apply some form of lubricant on the head of my penis and the top of my shaft mid down. I stand up. Insert myself into the first tube. Once in and comfortable I hold the tube against my pubic bone and begin. Using a brass handled bilge pump I slowly draw the air out of the tube. It can be anything that draws the air out. You want a good tight seal starting off with a low air pressure. You will feel a surge as your penis reacts and moves in length towards the end of the tube. The skin at the base of your cock will expand and flare out. Your skin will cling to the plastic as you start to grow. The crown of your cock head will get bigger and turn reddish or purple because that is where the blood flow is racing towards. You will feel a stretch as you lurch towards the end of the tube.
It is important to take things very slow. To use a low air pressure at first. Anything to strong will not feel pleasurable. Trust that you will know your own tolerance levels. Patience is a must. Me I have been pumping for years so the process proceeds quicker over time. My base fills out immediately. I slid up the tube into a good spot and then wait. In a few minutes time I grow as long as I am going to get. I use a method of building up and dropping off. I take the air pressure up and then let it back off slowly but not completely. This refreshes my cock with new blood flow and I think speeds up the process. The bottom of my circumcision line begins to swell. It will until that part of my shaft fills out and completely touches all sides of the cylinder. Once that is accomplished the remainder of my shaft will begin to fill out. Eventually the whole core of my cock will expand. Leaving just the end of the tube tube with open air space. At this point you want to leave your tube on and enjoy the full feel. You can also test your pain threshold and try to stretch out and finish filling that last bit. You can leave it on to encourage growth but you then run the risk of over doing it. You may pop a blood vessel which is not as painful as you think. Or you could push and then get a dreaded water blister under your sensitive skin. Avoid those at all costs. They are extremely painful and take time to heal. Which will take you away from your new found activity.
Once I reach the end of this first tube. I stair step progress to a larger tube and so on. With years of practice my sessions run 3-5 hours depending on circumstances. Ending in a 3 1/4 inch diameter tube. Cock only.