You may want to start slow and build from there:
Kegal hold for a slow 3 count
Rest 2 count
set - 25
Do one set and then another a few hours later through-out your day and build from there. But Kegal when you can and that P.C. muscle will be in shape and you will have ejaculation control like a adult entertainment star in no time. Also, you will be able to go again right after cumming and begin having multiple orgasms and shoot your load across the room. Talk about a turn-on for a woman, I had a few women just give me a hand job so they could watch me shoot my load
Push yourself to the next level when you get comfortable and it's feel too easy to accomplish the set. By increasing the sets and hold counts. You will know when, long as you stay aware and listen to your body.
I usually stop the sexual stimulation(don't wait too long at first) and held the kegal several seconds sometimes longer until the feeling of ejaculation subsides and resume the sexual stimualtion. I repeat this 10-15 times during sex some times. And I use the line, "Girl you got me so excited I can't control myself and have to stop for a moment so I don't cum too soon" Also, "I want to take care of you first before I come". Most of all be secure in your statements.
You need to learn to relax and control it. After a while it becomes 2nd natural in your thinking and you dont even notice you're doing it. All of this takes time, practice and most of all patience. She'll love you for it once you learn to conquer it. She can't faulter you if you are making an honest enough to correct it.
Become the master of you own body... learn to control it and don't let it control you.
Identifying the P.C. Muscle
The key is learning how to isolate the P.C. Muscle and exercise it correctly on a regular basis. Exercise the right muscle correctly in order to achieve an optimal beneficial effect from exercise. Just like any exercise, ease into it and become familiar with it. Then push your self a little more over time and do them on a regular basis.
When you urinate, try to stop-start the flow of urine by squeezing your P.C. Muscle.
Also, another way you can make sure is when you have a semi-erection, it is the muscle that makes it "jump."
Do not tighten the muscles in your abdomen, buttocks, or thighs; also, do not hold your breath.
Hopeful this is not too much to digest ...