You can trim pubic hair or loose weight(if you're overweight that is) or you can just pull back the skin(if you're not fully circumcised or circumcised at all)
You can't. Over time, months or a year or more the penis can be stretched a little bit, but only a little bit. Almost certainly not enough to justify the effort.
No. The size of your penis can not be changed in any way, only by operations and actually they don't make it bigger. The just do some tricks to make it appear bigger.
Yes. masturbate 18 times a day, in 7 months your penis will have grown roughly 3 inches in size. [source] Oxford Biology Research and genetics Dept. Dr.Aaron Dillon