It was one of those nights.
When you came home late from a long day at work, muscles aching and bones creaking. Sure, the hot shower took most of the tension away, but you couldn't get it all out.
And then you think back to him. With his cute face and small stature and button nose. And your remember when you had that course on saving someone when they're drowning in the Academy. You got planted with being his "savior" when everyone was partnered off. And down at the bottom of the pool, when you were "rescuing" him, you got to touch those abs and grab his biceps with your big, strong hands and his ass brushes over your swim trunk covered crotch.
Then you're up and running. Your hand is on your cock and you're thinking about what he would look like when he straddles you, when you drive him down on your dick, when he bounced up and down, when he came. What he would sound like, all the moans you could leak out of his mouth, how hearing your name screamed by him would drive you over the edge.
And then you're hand is covered in your own cum and sheets are dirty and all you can think is What a stupid idea. Bumblebee would never sleep with a giant monster like me.
That thought stuck in his head, Bulkhead begins to silently cry as he changes the sheets and then goes to sleep under the new ones.
End.
Okay, so this just popped into my head and I had to type it out before it escaped, so there probably are mistakes. Note: this works in a TFA Human AU. Whether or not that's Human Error Part 1 & 2 for you, doesn't matter. They're just human. Might continue with a few chapters and see if I can get ol' Bulky hooked up with BBB.