Invite, Lure
You say you've left some grain on the stairs. This is how you invite people into your place.
Picture yourself saying out loud how you've left grain on the stairs, trying to lure people in. You're surprised people are actually falling for this.
ゆう
さそ
None
You've invited people in by leaving grain on the stairs but some youths (ゆう) have ended up eating all the grain.
Imagine the youths just loitering in the stairs having eaten all the grain and taking up all the space making it impossible for anyone else to come in.