It is indeed a cultural thing. Not sure of the reason, but I believe it is related to the custom of removing one's shoes in the house. To avoid tracking "dirt" into the next world.
lap lap lap lap...Pingala... Seemingly, the Sanskrit name for Aiji, youngest child of Hariti (a.k.a. Kishimonten). Couldn't find any definitive links in English, so not sure I romanized it right or even interpreted the reference correctly. Halp!Your mother missed another chance to go and see you......but this time, I promise......I'll be coming soon...clatter clatter...siiip...