Ejaculating dildos

Lately I’ve been getting interested in the famous “ejaculating dildos”, which are the typical dildos but with a syringe, pump or bulb attached that can be filled with liquid, either water or fake semen, and simulate ejaculation through the dildo. I suggested to my girlfriend to buy one to expand the diversity of games in intimacy, to which she agreed without problems. Both her and I are most attracted to using it to penetrate each other (me to her and her to me) and discharge its contents inside our body (in her vagina and in my case in the anus), creampie, in a few words… My question is… has anyone already used toys of this type and experienced what I mentioned above? What fluids did they use to fill it? Are there any precautions we should consider? (Beyond keeping the toy properly cleaned after each use) I hear you…