I guess it depends on the nature of the sexual experience itself. There's a saying of 'don't have sex with someone you would have a problem being.' Since you mix vital energy with that person from the experience, I guess someone whose energy is good for you would be health, and if theres negative energy brought in (manipulative partner, hate-sex etc) then that will poison your energy and you need it clearing. No matter what interaction you have, energy is involved
The OPs friend is either not training enough or not having enough sex if he's not having sex 2-3 days prior to training.
