My first thoughts are if my baby is ejaculating for distance that means he cannot be cumming in my mouth or pussy. Not good
I would, however, help measure or evaluate for fun if he wants, we can make it "official". I am all for him masturbating when he needs to/when he wants to (and I so want to be around for this too) so we can do some measurements then if it's valuable info. I am supportive, just doesn't get me excited.