So i am gonna get a penis pump because it seems way more fun, what kind of temporary length gains can i expect? 0,5 inch for couple of hours is realistic?
The good thing about the pump is that after every session you see an enlarged penis.
When you first start you should build up slowly to allow your penis to get used to the vacuum, 10 minutes max. have a rest day or two then repeat, slowly adding time.
Don't pump to a high vacuum (>5 Hg) and try to keep as hard an erection as possible. After a few weeks you'll be up to 20 minutes (2 x 10mins). You'll start to see a greater expansion, a small amount of lymph fluid will plump up your girth and your glans will swell much bigger than normal - which will make your penis appear slightly longer after you remove the cylinder, I haven't seen more than 1/4" increase in length.
Girth however can expand massively after a month or two if you start pumping for hours, lymphatic fluid fills and expands the penis skin, especially in the foreskin area creating the donut effect. This lymph build up can take a day to drain away giving your flaccid penis a heavy feeling.
I have had a successful 2 months of pumping without this lymph expansion, I find pumping with a maxi-erection in a large tube too intense to go beyond 30 minutes, you can really feel the tunica stretching. If I manage to stay rock hard for the 30 minutes, that'll be a great workout and the girth increase usually remains even the following day when I don't pump.
I haven't increased my length however, I just ordered a smaller diameter cylinder so that the expansion will be limited to length.
You are right about the fun part, playing with a bigger-than-before cock is very satisfying.