This is an unexplained episode. If it happens again, you many need to consult an urologist.
Hi Jess_e, you cannot ejaculate without your brain first activating the ejaculation program, which requires sexually related thoughts, or sexually related feelings.
For example: I once had a client who had a similar experience as you - but while he was eating breakfast. After some digging to determine the trigger, we determined that he had an underwear fetish, the feeling of the fabric against his skin was super arousing for him. So although he didn't masturbate leading up to the unexpected ejaculation, his continued thoughts and focus on how good it felt, caused him to ejaculate.
I'm not suggesting this is the same for you, but you may want to keep it in mind if it happens again.
its rare, but its possible to ejac without sexual stimulation. if you havnt fapped for a while, your