I love it when the “top searches” list makes little or no sense, because that encourages whimsical free association.
4chan honeypot, change behavior stories, where early christinity gets its legitimacy, boy hand in girl anime
I hope “boy hand in girl” anime is an anime story where a boy and a girl walk hand in hand. However, I suspect that something else was meant.
I don’t know of any anime where a boy has a hand in a girl. Probably there is some hentai anime where that happens.
However, there is a famous manga where a boy’s right hand turns into a girl, and that manga is Midori no Hibi.
There is also Bakemonogatari, a show where a girl has a gorilla hand. If the gorilla is a boy gorilla, then I guess that counts as a “boy hand” that is “in” a girl’s arm, where by “in” I mean “at the end of.”