Always use a blowoff tube, there's basically no downside and it handles overfilled fermentors without issues.

There are two groups of homebrewers: Those who have had to mop their ceiling, and those who will.

I'm sure you have learned this with hindsight but I wouldn't fill your carboys that full.

When I have a very full batch I sometimes will use a long hose into bucket of water airlock so that it's less messy if it bubbles over, but best to just not have it that full to begin with

I will join the choir of "Use a blowoff tube". At least for the first few days, until the yeast settles down. Then you can swap in the airlock.

What's this.

This is the way

I'm going to pretend OP took this like one minute after the previous post. They received the advice to gently rock the vessel, shook it vigorously like making a cocktail, and were then left with a thunderous bang covering the entire room