During the "Present For You" chapter

During the "Sake and Tears and Men and Women" chapter (not gonna spoil it)

During the ending of the fourth season of the original anime Referring to the ending song "Open Invitation," which is mistankenly the second ending of the third season, not the fourth.

During the last episode of the original anime

During the first season of the new anime This one didn't happen, but I hope they have an accidental kiss at one point