Pasquale sleeps with us and he usually does get up once a night to use his pee pee pad in the bathroom. On his way back...he'll pop into the walk in closet to see if I by chance dropped a sock he can play with LoL Then he'll pop back up to bed with us ...of course taking the LONGGGG way up my body and sit on top of the pillows until we lift the covers up for him to crawl back under.
One way you could stop your little one from going under your bed is to put thin storage crates under there. Thats what i have under my bed. It will block your little one from going under there AND you can store some things.