Chafing occurs near the anal sphincter. In the crease of your bum. It can happen to anyone. It happens to me.
I also get chafing round the testicles. Where the testicles rub against my legs. Not everyone gets chafing there. Women may get chafing in odd areas. Certainly not around testicles.
Okay, that's the worst over with. Now we all understand what I'm writing about. I can now use euphemisms...
My chafing shows up as dark red skin. Sometimes it itches. Not always. Chafing round the back is the worst for itching. As far as redness goes I'm not sure... I don't often (or can't) stare round the back.
Chafing round the back is caused -- as far as I can tell -- by skin rubbing. By the two sides of the back... side... rubbing against each other as I run. That rubbing can't be helped. It's just the way the body moves.
So I apply Vaseline. The all-purpose, all-powerful preventer of all chafing. And it works. Up to a point.
The longer the run, the more Vaseline at the start. The longer the run -- the hotter the day -- the more chance there is that the Vaseline will wear away and chafing will happen.
And then there is -- the toilet...
Go to the toilet, use toilet paper, the Vaseline is wiped away. So carry spare Vaseline? Well, that's a good idea before the run. Not so convenient during a run. (Unless it's one of those very long runs, where you carry a backpack full of useful items.)
So, do I avoid going to the toilet during a run?
No!
First, it's uncomfortable. A distraction from my easy running style.
Second... it encourages chafing.
If I need to go to the toilet -- but don't -- the natural action is, to clench the appropriate sphincter. To tighten muscles in order to hold in the number ones or the number twos.
Whichever sphincter I need to clench -- the other one will also clench. Actually, I can somewhat separate the actions of the two. But without some effort -- again, distracting from my running -- I clench one sphincter, the other will also clench.
So I want to pee but hold it in. By tightening a sphincter at the front. The sphincter at the back will also tighten And this is where the trouble really starts!
Tighten the rear sphincter. I can feel my bottom -- all of it -- tightening. The sphincter muscles tighten, the (I think it's) gluteas maximus muscles also tighten. My bum begins to look so tight and terrific!
And the two cheeks are tensed. They start to rub harder. And I get chafing...
If I hold in number ones or twos, the whole area gets tense. This causes firmer rubbing between the two halves. This, in turn, causes more chafing.
Okay, near the end of a run I'm happy to hold it all in. (If that's not possible -- I'm in a whole different lot of trouble!)
With a lot of running still to go, I prefer to let it all out. So I can relax into a comfortable running style. So I can relax the areas that would otherwise chafe. So I can worry about the run, rather than worrying about the time to the toilets past the finish line.
Does this mean that I lose races by the time I spend in toilets? Not really... I lose by far more than that. It does mean that people can overtake me while I am standing -- or sitting -- still.
So what?!
I'm not there to win. (No hope of that!) I'm there to enjoy myself... Mostly, I enjoy the feeling of success once I've finished.
But if I go to the toilet during a fun run -- when I need to -- then I also enjoy the actual run... a bit more than I would otherwise.
And I enjoy the post-race exhaustion -- without excessive post-race chafing.