Waking up covered in grass and dirt is not a novel situation for Peter, however, waking up covered in grass and dirt in his own apartment is. So when it happens every day for eight days in a row, he starts getting worried.
At first, he assumes that someone has been drugging him and taking him to the woods but realizing he didn't smell like the woods and didn't feel like he was getting off of the wolfsbane high but he figured Stiles would have noticed and mentioned something if Peter was crawling into bed with him every night covered in dirt and grass and high off hiss ass.
Thinking more about his predicament, he came to the conclusion that Stiles (his "boooyfriend", he could hear Laura's voice drawling in his head) had, well, something to do with it. He had no idea what, though.
Therefore, he would investigate!
He tried pretending to sleep, which ended with him falling asleep and waking up covered in grass and dirt again. He tried setting his alarm clock to wake him up before the time he knew Stiles was going to be waking up to see what happened but it only led to him waking up covered in grass and dirt with Stiles still in bed with him.
Finally, he gave up and decided to just ask Stiles outright. Which was met with lots of blushing and a murmured answer even his super-hearing couldn't decipher.
"Okay, maybe you could try that slower?"
Stiles sighed and hung his head, avoiding eye contact.
"So, I read on this website, well, see, it's a flower meaning website, and, well, it said grass meant…well."
And that was when he decided to take the opportunity to escape.
As he watched Stiles run out of their apartment, Peter sighed and turned to his computer. He was going to get to the bottom of this!
After some pretty short research (it wouldn't even fit in one of those 80s montages, really), he found that grass meant, well, submission. Also, he found it could mean homosexual love but he figured that was a long shot, why on earth would Stiles love him?
It gave him a start, the thought that Stiles wanted to submit to him. It just didn't seem in-character for Stiles who was mouthy and defiant in bed and out of it but, he figured, if this was something his boyfriend wanted to try out, he would be happy to oblige. They would have to have a talk first, though.
The talk did not go well. At all.
It started ALMOST well, with Peter saying he researched grass meanings and felt like he knew what Stiles wanted to say but, as soon as Peter veered off into the topic of submission, an argument broke out. Stiles kept insisting this was not what he wanted while Peter kept insisting otherwise.
They were yelling at each other, angry and riled up, until Stiles, in a moment of desperation, screamed out "I love you, you idiot!".
After almost half an hour of frozen silence, Peter asked in a small voice "Really?"