Okay, so it turns out Shigeki Sunada actually animated the part where Araragi swings Hachikuji. I had looked into Sunada's role in this episode when I was initially clipping this scene but I was really confused by the term "ジャイアントスイング" (giant swing) on his sakugawiki page, especially since this episode takes place in a public park. Anyways, I was today years old when I learned that it was actually a popular Japanese colloquial wrestling term. The more you know I guess.