Edging is a exciting way to prolong your orgasm and experience a more intense one. If you are experiencing any kind of difficulty during it or excersing, then the first clear rule is avoid it.
Secondly, there are many pelvic muscles exercises and other breathing techniques to make your ejaculation powerful. Also try to do mul bandh under a good experienced yoga trainer with certain kind of pranayama, that would surely help better than excercise.
Next Steps
do pranayama regularly
practice bandh regularly
Health Tips
meet a experienced yoga trainer or physio for pelvic strengthening floor excercise.