Try to find Locktite/Permatex 518. Its an anaerobic sealer - means it will only harden when its deprived of air. So if you let a little bit ooze out, that won't harden & plug your oil passages...

If you use RTV make sure you get some kind that says its safe for O2 sensors. I've heard that you can destroy your O2 sensor pretty quickly if you use the wrong stuff.