I think that that scene, despite containing sexual content, wasn't intended to be sexually arousing. It's a weird scene, but when you approach it rationally, what else would you do if you wanted to form as strong a connection with your buddies as possible to keep It from winning? What makes the scene interesting is that it's about survival, but the method of survival also happens to be conducive to forging an even more powerful bond between the Losers. And they needed all the power they could muster to defeat It.
There's no rationality in that scene. Its simply the product of a fucked up mind made even more fucked up by lots and lots of coke. ---
