My old cat... was a scrapper!
Abcess one on his knee, I realised his knee looked an odd shape, he wasn't chuffed with me poking and prodding so off to the vets... I got there just as the vet was shutting up shop but he knew me and so we went back in.. now nice vet had taken off his work green top thingy... was in his normal clothes.
I think you know whats coming next.
He flexed the limb, he poked it, prodded, it he found a soft boggy bit and said ' i think this is a whopper of an..... SPLORRRRRRRRT.... abcess... It dripped all down the front of his shirt, green and yellow.. and lumpy. And omg the smell.
How I did chortle.
A week later, Mr Cat is sitting on my lap in front of the telly, stands up to do the usual cat, turn three times around, show mother your borthole and sit down in exactly the same position thing... it EXPLODED.. into my lap.
Cat, lap full of green and I got up, to the bathroom and into the bath and the cat sat totally still as I showered us all off.
One of current Ddogs gets sebaceous cysts which are usually a bit itchy for him and he will present himself for a squeezing.. it comes out like toothpaste but rarely smells bad at all.