The pull out method does not work. With sex even if you don't ejaculate the woman can still become pregnant.
You can just stop right before it happens. Thats about it. Healthy and normal to let it happen.
There is nothing wrong with ejaculating - it is a totally normal physical behaviour of your body. Regular ejaculation does not, itself, cause any bad consequences.
I don't think that stopping will cause any bad effects, although if you ejaculate only very rarely, your body may reduce production of semen, which may then be an issue if you become more sexually active later, although I expect production would pick up again.
Under what situations are you ejaculating? Are you sexually active? Do you masturbate regularly? Are you having issues with ejaculating when you are not having sex of masturbating?