I just found website which is on meditation. It has given some technique of coffee enema, coffee implant etc. You may study it and if found logical you may use it.
http://drlwilson.com/ARTICLES/COFFEE-VAGINAL.htm
You may try male deer exercise. There are few others, you may have look at them and take up any techniques you like.Google the word or phrase.
male deer exercise,
kegel exercise
Sat kriya.
Circulating wareness around microcosmic orbit.
Anal breathing.
Testicular breathing.
Navels youga lock.(kundalini yoga)