Sorry, if this is too much information.
Suffice it to say, I don't know the answer. I've read countless threads on humping behaviour, but don't recall ever seeing any discussion on whether neutered males ejaculate or not.
Brody is a bedtime humper. He likes to go to town on the pillow next to my head. I don't like this, mainly because it is right next to my head and listening to my dog grunt and grind while I'm trying to read isn't at the top of my "love to do" list. So, I tend to stop him, which isn't always that easy as he's enthusiastically pumping away. Verbal sometimes (not often) interrupts him, but usually I need to give him a tap on the rump or physically pick him up and move him away to get him to stop.
Anyhow, last night he was going at it and I was distracted and never stopped him before he finished. He then jumped off the bed and went racing around the house then came back in and started sniffing the pillow he'd been molesting. I turned over to look and the pillow was wet (quite a big spot). So, I'm not sure if he ejaculated on it or peed on it. I couldn't tell and I wasn't sticking my nose in there to find out!!
Anyhow, not really what I wanted to deal with at midnight. So, I got up and treated it as I would if it was urine (tossed pillow cover, treated pillow, etc.) and then went back to bed.
But, I'm really unsure...did he pee or ejaculate????
My dog is a perv!