Semen is usually a white or yellowish fluid.
How long a man can be stimulated before ejaculating, how long the ejaculation lasts, the strength of the ejaculation, and the amount of semen that comes out, all vary from one man to another.
Most of the semen is ejaculated in the first few squeezes.
When he has an orgasm, comes out from the end of his penis.
It can corrode the toy and cause damage.
Of course, sensations of touch, pressure and vibration in his penis prime your guy.