I just found an energy exercise.This is taken from Chair Tai Chi website.It is similar to circulation of sexual energy around microcosmic orbit.Ask your boy friend to do it. It will strengthen his sexual stamina. or may Google microcosmic orbit to get full details.
Begin as usual
seated in a quiet area of your home in a comfortable chair with your back fully supported by the back of your chair .
Breathe in and out through your nose for 6 to 12 relaxing breath using your lower abdomen.