This one used to be quite common in fanfic circles - especially in the, uh, smuttier stories. You'd come across people who were "writing in passion", which is a mental image I've always rather loved. Less commonly, you might also find people "writhing an essay".
I've seen this in published work as well as fanfic, and it's almost always about "viscous fights". I did ask one culprit if her protagonists were wrestling in treacle. She didn't get it...
Another one very common in fanfic circles. I think the all up best (worst?) version I saw was someone who was describing a character who was a black belt as an "expert in marital arts", although the person who had a couple going off to their bedroom to practice "martial arts" comes a pretty close second. A close third would be the story that had The Emperor "declaring marital law" in the galaxy.
Lastly, my second favourite ever "typo" (can't post my first fav because the filters won't let me!):
"They parted monuments later."