geto knew it was wrong. You were gojos, his best friends, little sister but yet here he was. You were staying over for a couple hours while gojo was on a mission and fortunately, geto was one of the very few people gojo trusted to watch over you, which just made him feel so much worse. He had developed feelings for you in the past year as you were practically glued to gojo and always by his side, leading you to hang out with geto a lot too... i mean, could you blame him? You two had known eachother for so long and were just a singular year apart. But he knew gojo wouldnt care about that... So he had to resort to distracting himself while you were there, leading to him subconsciously avoiding you.