how to enlarge my penis without side effects

What is the normal penis size in relax and erection time :
1. erection : 8-18 cm
2. relaxtion : at least 6 cm
How to increase penis size without side effects  ?
there is no way to increase penis size without side effects , as if you want to use products , there is no recommanded products as its all totally unreal claims , there is no products have the ability to increase penis size , and its all false claims , and the only options to increase penis size in effective ways are the surgical options , which are :
1. there is a surgical option that may increase you penis size about 4-6 cm by cut out the internal tendons that connect pelvic area to your private area and leave bigger space to penis to increase 
2. there is a plastic surgery that increase penis size by implanting silicon implants in the upper areas of penis goes into the internal area of penis and it increase penis size around 6-8 cm
* those surgeries have side effects and complications such as infection , bleeding and changes in penis shape and so on
What are the costs of those surgeries ?
1. first surgical option ( cut out the internal tendons ) : 2000 - 3000 $ or more 
2. second surgical option ( implanting silicon implants ) : 10000 $ of more 
General advices to increase your sexual ability :
following the healthy and appropriate way to do the sexual intercourse with your partner  and having a regular healthy diet  and also doing exercises and give up bad habits like smoking and drinking alcohol , plus avoiding stress and anxiaty sources