How do you mean in regards to "evenly distributed" in regards to health? Actually, what do you mean overall? I have a pug and know full well that he will be emitting fish smells when he gets older that will sometime appear in solid form. I'm just not there yet. But am eager to hear more (I will of course google otherwise).

Obviously my pug's butt has some kind of smell because all the other dogs keep smelling it :D My complacence is more with that if he sits his butt down on my pillow, I'm not going to freak out about it. Should I be concerned about this?

What I mean is that dogs have anal glands that need to release really awful smelling fluids, probably what you and your other dogs are noticing. When it happens naturally you will see a drip if you watch your dog do the deuce.

The uneven distribution is that not all dogs do it naturally, some need occasional assistance (you can do it but I’d recommend a quick/cheap vet visit, it’s gross and a bit of finesse). Some dogs just don’t get it done naturally and need that assistance on a regular cadence.

The health implication besides being a natural bodily process is that if it backs up, the whole solid waste system backs up.

Edit: don’t be overly worried, but do be attentive. If you see butt scooting this is probably what’s going on. (If it’s not it might be something more serious like a tapeworm. But I doubt that from what you described.)

And dogs are very attuned to the scent. If you smell it too it’s probably a good idea to go let a vet nurse squeeze out your pup’s anal glands. It’ll be a relief for pup and not at all traumatic.

If needed, dogs will perform their own anal gland expression by sitting, pulling their hind legs up, and wiping their butt across your carpet. My dogs like to look at me when they do this like it's a fucking joke.

I've seen videos on youtube of people expressing a dog's anal glands, but I myself have never once been able to do it. There must be a special technique that I just can't get.

Our dog had an ingrown corkscrew tail (English Bulldog) which was amputated (laser surgery!) and anyway, I'm telling you this because our groomer does anal expression and said at first, it wasn't working for her because there was no tail to grab onto.

There is definitely a technique, but for $5 or $10 extra at the grooming appointment I think I can afford to go a while longer yet before I try to figure it out for myself - I mean, I know you can go on YouTube and learn pretty much anything but I just can't see myself...