I'll give you 2 hints about it, and you can probably figure out what happens:
Hint 1:
Tebbayashi-hen was a fan made story that based on one interesting "theory" that came around near Tatarigoroshi-hen's time. A person posted on 2ch about how when he was playing Tatarigoroshi-hen, but he felt something was weird. When Keiichi was killing Teppei, Teppei barely put up a fight. Why would something who's way bigger, used to fighting, would be so easily killed by a teenager who is less built and study-orienated?
Of course, Keiichi having the bat is an issue, but it should not have been an absolute factor. It's not like Keiichi had a gun or a katana. If you think about the power of an adult vs. a teenager, Teppei should've had the upper hand. But why is it that Teppei didn't even resist (he did run away for a bit, but that's about it)?
"Should've been able to...no wait, now I remember...
It's not that he could not resist...it's because he didn't...
Even when the bat broke his arm or his forehead, he still kept saying that! That!
Without showing any fear, and with a slight smile on his face...believing that his next words would reach my heart...
That's what he was trying to do...
It's alright,
'Believe me...'" (rewatch episode 25 of season 1 if you don't know what this is about.)
Hint 2:
Teppei + Matsuibayashi = Tebbyashi
