I recently got a baby male guinea pig and I take him out and he runs around and jumps but when I stroke him he always purrs and squirts white liquid into my hand. Or when I put my hand near him, he jumps over it and squirts white cloudy liquid into it. I'm not sure if this is a mating thing or that he just can't control his wee when he purrs.
It sounds like he is spraying semen fluid liberally around. Please remove it while it is soft; when dry, it truly lives up to its name 'boar glue'. Please check his boar bits weekly if he is that active, as the dried semen fluid may also form painful sperm rods in the penis shaft.
A soft toddle-safe piggy sized humping toy should help to draw some of the testosterone driven fire.
More information with pictures in this link here:
Boar Care: Bits, Bums & Baths
More information on boars:
A Comprehensive Guide to Guinea Pig Boars
Our very useful new owners guide collection of which these two guides are part of, but which covers a lot more areas from settling in and making friends with, understanding behaviour, companionship, diet, housing and care, learning what is normal and what etc.
Getting Started - New Owners' Most Helpful Guides
Is he a single piggy or does he have a companion? Please be aware that guinea pigs are group animals and not wired to live on their own. Your boy is currently doing to you what he would do with a boarmate. He is not unhappy in himself, but he is clearly lacking the round the clock companionship and interaction that he instinctively understands and is going to miss out on this vital aspect of his life for the next 5-7 years of a healthy life span. This constant need for companionship is not going away when you are busy, have other commitments or interests or are leaving home and can't take him with you...
If you can at all, please consider finding him a same sex companion; it is the best and biggest gift you can ever make him!
