Ibn 'Umar reported that when his children had reached puberty and he had withdrawn to his room, none of them entered where he was except with his permission.  

أَنَّهُ كَانَ إِذَا بَلَغَ بَعْضُ وَلَدِهِ الْحُلُمَ عَزَلَهُ فَلَمْ يَدْخُلْ عَلَيْهِ إِلا بِإِذْنٍ