Looks like my boys, so seems more male.
To extrude the penis, you have to place your finger(s) on ridge, and gently push, and it will slowly come out. It takes some time and lots of patience.
And its good to learn to do this because once in a long while its good to see if the penis is clean.
Take him.her to a vet, the vet will def. know, and also might be able to show you how to extrude the penis.
And he might not be neutered, some guinea pigs don't have prominent testicle.
Goodluck
To extrude the penis, you have to place your finger(s) on ridge, and gently push, and it will slowly come out. It takes some time and lots of patience.
And its good to learn to do this because once in a long while its good to see if the penis is clean.
Take him.her to a vet, the vet will def. know, and also might be able to show you how to extrude the penis.
And he might not be neutered, some guinea pigs don't have prominent testicle.
Goodluck