Okay, admittedly this is somewhat embarrassing to ask, but I may need advice on writing a good, solid (Preferably hot, although nothing over TV-14 levels) make-out scene between Twilight and Rainbow for my story the Return of Doctor Whooves. Basically, for the last two stories in the series, I've been building up a relationship subtly and slowly but for an upcoming chapter, just when everything's gone pear shaped (As things usually do when the Doctor's around. Attracts trouble like a slice of cheese attracts mice, that stallion.) I want them to have not just a Big Damn Kiss, but a Big Damn Make-Out. Er... Trouble is, I don't know how to write such a thing. Any advice?

You could always use a delightful set of euphemisms to imply the kiss without actually describing it in graphic detail. This allows readers who really want to read into the ship to see some sort of beautiful make-out kissing scene and readers who just accept it part of the story to see it as something more tame.

You can also focus more on the actions of their bodies as opposed to their actual mouths. Being pressed up to one another, hearts beating against one another, can lead to some pretty romantic situations. But, it can also just be a very close hug. It really depends on how far you want to push the envelope.

5762376 Oh believe me, I want to push it quite far, about as high as the Teen rating will allow.

5762086
The key to any good kiss/make out/sex scene is to focus on what the characters are thinking or feeling rather than what they're doing. No matter what you describe hooves, mouths, wings and other bodyparts doing, it's going to be boring or awkward if you're not using descriptive language or narration from the character's perspective to make it clear how they're reacting emotionally. At the same time, as 5762376 implied, you can get across the attraction and hotness while leaving a LOT of the physical stuff to the reader's imagination. (Regarding hotness, it's 100% in how it's written. You can write a character changing a car tire and make it sound like porn.)

So, all that said, if you're having trouble you could try writing or mapping out the characters' emotional reactions first, without even bothering with what they're physically doing, and add in actions for them to be reacting to later. (Or use some placeholder actions and go back and edit them when you're sure the emotional stuff sounds good.)

But at the very least focus more on how they feel than what they do, and people will like it just fine.