My Friend's Gotta Cum to Use Magic

Synopsis

“Why does this feel so good? What magic did you use?!” His childhood friend knows nothing of sex, but that doesn’t stop him from making her come over and over again… Allow me to teach you everything while you melt around me!

Also known as Minha Amiga Tem que Gozar para Usar Magia / 異世界ねぇちゃんは、イク時しか魔法を使えない