Engaged, then disengaged!

Danielle
Getting ready to give birth to my second baby... I feel like my son keeps engaging and then disengaging, and I'm starting to wonder if he's not in a good position? I've read about floating babies, and I've also read about babies growing too large to fully engage... I know, I know, I should really just stop reading stuff! 
Tonight I got this silly idea that the slant of our couch might be messing up his position... Is that totally crazy? Or is it a rational thought?