It's a boy thing

Yesterday Merlin & I and the kids were at the mall. We were upstairs near some escalators when Merlin and I stopped to look at something. The kids went over to the railing to look down. Next thing I know Big Sister says, "Brother just spit over the side!" I immediately gasp and tell him to stop and that we don't do things like that. Merlin tried to agree with me but couldn't look Brother in the eye because he was laughing so hard.