A lot of men have learned and trained themselves to connect orgasm with ejaculation. For this reason, some might feel the urge to reach ejaculation during a tantra session, as the build up of sexual energy gets more and more intensified.
And there is nothing wrong with ejaculating. It can actually be very appropriate to consciously experiment with ejaculating once in a while, as a part of ones tantric process; To hinder that ejaculation will be related with something shameful, or not to become too fanatic about never allowing ejaculating.
But at the same time it's essential that a man is in charge of his own body, his direction and energy, and therefore learns to master his sexual energy; to be able to become the best version of himself, get the most out of his sexuality and his life in general.
The reason why I don't consciously provoke ejaculation during my sessions, is that it is an interruption of the energy flow I am creating. I am working in a meditative, heart centered, feminine stream of energy, and if I should provoke an ejaculation, I would have to step into a more physical, chasing, mental and directed energy, which is something different entirely.
There is plenty of this energy out and about in the streets, in work life, in traditional sex and everywhere else, but I keep this type of "mental chase energy" out of my sessions. For this reason I don’t feel it would be a "happy ending" to force ejaculation through, but rather a destructive or disruptive act towards the high vibrational flow which is created in the session.
However, it is very different if ejaculation happens spontaneously, while we are in the flow. Then it's only a matter of the man not yet being trained enough to be able to hold back, or the man chooses consciously to give in to ejaculation, and both are completely acceptable in my eyes.
To me it's not about if it is okay to ejaculate or not, but rather about how it happens.
If a man is used to ejaculate every time he has sex and masturbates, then I recommend some practices to do at home to learn to split the ejaculation from the orgasm. In this way a man can both learn to preserve his energy after sex, and can get to experience much deeper orgasms, which can trigger great healing, energy opening, regeneration, and take one to another vibrational level.