Bei http://en.wikipedia.org/wiki/Testosterone#Production heiß es
A 2001 study[2] examined the effect of a 3-week period of sexual abstinence followed by masturbation-induced orgasm. It found that abstinence over such periods "does not change the neuroendocrine response to orgasm but does produce elevated levels of testosterone in males."

A 2003 study[3] showed that serum testosterone levels reach a peak seven days after abstaining from ejaculation.
Daraus könnte man schließen, dass alle 3-4 Wochen optimal wäre!