Here’s a Touhou doujin, courtesy of pesu and Ean once again, featuring the Youkai of Winter, Letty Whiterock. Pretty quaint little doujin here.
A shota happens upon Letty by the river as he’s going to get his watermelons. He mistakes her for a thief at first, so to apologize, he invites her to try some watermelon. In return, Letty offers to be his big sister for the day and do anything he asks. Of course, the first thing he asks for is to see her breasts. As expected of a shota interested in tits *nod nod*. Things naturally escalate from there. Not too much though.
In any case, Links and ExH Gallery below.