One thing you can do with your set sis that you like but don't want them to know is to secretly plan a surprise gift or activity for them. For example, you could book tickets to their favorite concert or movie, or buy them a special gift that you know they've been wanting. This way, you can show your love and appreciation for them without revealing your secret plan until the big reveal. It can be a fun way to show your set sis how much you care about them and make them feel special.
