Knocked … What?

Last weekend, Sean was running laps around the house. On one pass, he bumped his sister on the way by, and knocked her flat on her butt. So we asked him to stop, come back, and tell Carter that he was sorry for knocking her down. So he comes up to her, gives her a hug, and says "I'm sorry I knocked you up, sister." Lori and I just looked at each other and busted out laughing. Then we told him to say "knocked down", not "knocked up", as the difference is quite substantial.