Kegel exercises to strengthen the pelvic floor muscles (also increases ejaculation strength). general cardio fitness to strengthen your heart and better control heart rate,, and controlled breathing (slow deep breath in and slow breath out) are just a few things you can do. You can also practice ejaculation control by edging. Also some biological info such as noticing that often times the testicles retract tighter to the body when close to orgasm... by gently pulling them down between sexual positions this buys you a little time as well as it restarts the retraction process. But, breathing and kegel exercises will take you far. Breathing is something most people don't pay attention to because you naturally breathe faster when your heart rate increases as you build to orgasm.