mkeycrash: Pumping can be fun and also successful. BUT, if done incorrectly it can also ruin your cock's look.
You have already been warned 'bout trying to increase size too fast with too much vacuum, and it's also important to not keep it in the tube too long at a time.
Begin with just enough pressure to enlarge to a hard on, and go fifteen minutes -- never over 20--before taking it out, rubbing more lube on it and 'rearranging' the skin for 5 minutes. Then slid the tube back on and pump for another 15 minutes. NEVER use enough pressure to pull the little capillaries to the skin's surface where they burst. No one wants a red spotted cock!
For the first time one 15 minute session is enough. Three fifteen minutes sessions and even four of five after your dick gets accustomed to being pumped.
The suggestion to wrap gauge around the foreskin will keep it from ballooning and being puffy. However, if this does happen, it will deflate in 2 or 3 days and be ready to go again.
As your dick gradually increases in length and girth you will graduate to a larger tube. The tighter the tube around your cock, the more it's length will increase, whereas, if the tube is a little loose along the dick shaft
increase will be obtained in girth.
Go slowly, man. It will work, if you don't try to conquer Rome in a day. Skip a day between sessions and go for it three or four times a week.
Feel free to EM me I can be of any further help, or let me know in this thread if you like.
Good luck, mkeycrash, and happy pumping watching your cock getting longer and thicker!