I won't be writing out the entire episode, I'll just be saying one part of the episode I think would be the funniest.
And the reason I didn't put my OCs in some of the episodes is because either (a) I don't think they would be there, (b) I couldn't think of anything, or (c) I haven't seen the episode yet.

Donnie's Gifts

Donnie, pointing at Levi: "And you...You get nothing, you're way too annoying."

Levi: "...True. Harsh, but true."

War and Pizza

April: "Actually, I just needed Donnie."

Raph: "Oh, we know! We just came here for the free pizza!"

Levi: "Oh, no, actually, you guys did; I came here to pump up this party!" *runs out to the kids* "Hey! Kids! Wanna see me juggle a bunch of knives?!"

April: "...I'm so getting fired."

Shell in a Cell

Leo, falling: "I could beat any of 'em!"

Raph: "Leo!"

Leo: *"defeats" Ghost Bear*

Levi: "...Right, be right back." *starts climbing down*

Kevin: "Where- Where're you going?"

Levi: "I'm about to ruin this man's whole career."

Kevin: "...did you just—"

The Fast and the Furriest

Levi: *in the Turtle Tank with Splinter*

Donnie: "Yeah, I think we all know who took it."

The Evil League of Mutant

Donnie: "Oh, why can't something just fly out of the sky and solve all our problems?" (I'm pretty sure I got that line wrong but idc—)

*Posters hit all their faces*

Levi: *Was balancing on the edge of the roof on her skateboard, and when the poster hit her face, she fell off*

Kevin: "...I'll go get the first aid kit—"

Mrs. Cuddles

Kevin as he watches Mars. Cuddles scare Raph: "Pff- Raph? You're scared of her? Come on, she can't be that—!"

Levi hiding behind Raph as she holds up a rosary, a cross, a bible, and holy water: "BEGONE SATAN—"

Portal Jacked

Everyone else: *complaining about wanting to go back to Tahiti*

Kevin: "THANK GOD YOU GOT US BACK THE SAND WAS GETTING ALL OVER MY FUR—"

Bug Busters

Leo: *pressing buttons on the elevator to try to escape*

Levi, whisper-yelling dramatically: "Take me with youuuu—"

Leo: *saluting and waving as he leaves them behind*

Purple Jacket

Donnie: *bragging about his new Purple Dragon purple jacket*

Levi, posing with her own hoodie: Bish, PLEASE! You may be trendy, but I be FAB!"

Mystic Library

Donnie, showing his library card: "I have—"

Levi: *screaming at the top of her lungs as she starts a book fight*

Librarian: "...Yeah, go do what you need- But she has no excuse- She's going to the kids section."

Donnie: "I honestly think that would be for the best."