"Well, they've been asking to be grossed out, indirectly," said Mare.
"Oh, fine. We'll go with what you want this time, but I get to choose what we do next!" Alicey announced.
"Whatever. So how do you want to go about this?"
"You're the one who wants to gross them out. I'm just following along. So you decide."
"Well..." Mare was thinking. "...whatever that farmer fed us, it left a bad taste in my mouth. And not just my mouth, but my WHOLE digestive tract too. I have a stomach ache right now because of that stuff. I think you get my plan," commented Mare.
Alicey whined, "Oh, geez, isn't that one getting old? I thought you were going to make us pick our noses with tree bark, not make them unattractive!"
"Hey, you said you're following along, so no complaining! Besides, one of them was thinking about farting in my face, so you can blame him for the idea."
A low gurgle was heard coming from Mare's bowels. Something stinky was forming in there.
Alicey spat, "You know, you're not even remotely lady-like."
"...Says the mare who left ten pounds of digested food on one of the boys' face."
"Hey, I couldn't hold it at the time! It's not my fault!"
"And what about all the other times you left 'presents' on their faces?"
"Same reason!"
"Yeah...I'm sure of that..." Mare eyed Alicey with one eye. Seconds later, a much louder gurgle emanated from Alicey's bowels. "Dinner didn't agree with you either?"
"Not really. It never does, either," complained Alicey.
"Well then, let's go get them while we have the chance. Seems to me like those two idiots are already sleeping."
"Whatever. I just need to get this load out of me!"
***A few minutes later***
Bum and Don were sleeping soundly on separate haystacks. Neither of them noticed, but their heads were each between a pair of a mare's hind legs. Alicey was the first of the two mares to start dropping her load. She had so much packed up in her bowels that she could literally feel the crap slide down and out of her anus. Her eyes were squinting from the pain in her rear and her grunting. Mare was doing the same thing, except with much less effort. After about a minute or two, both were done. They moved away and to a safe spot so that they could watch the coming comedy.
Not long after, both of the boys woke up, wondering what it was they were feeling on their faces.
"Ugghhh," moaned Bum. He was still tired. "Is this a...free...Chocolate Sun-...Sundae...?"
Don was stirring around on the ground. He added, "I don't...know...but it tastes like..."
As soon as some of the crap got on their tongues. they both fully woke up, eyes wide and spitting out the brown contents. They then immediately stood up and tried to shake off the rest of the poop.
"Ah, dammit! They got us again! That's it, they both deserved to be farted on," declared Bum.
"Or worse. But they're still attractive," Don said. The two mares heard what they were saying and didn't like it one bit. Well, except for the last part a little bit. Competition was already brewing.