Hadith 10:1224
Abu Bakr narrated to us, he said: Isma'il ibn 'Ulayyah narrated to us, from Yunus, from al-Hasan, that he used to say: "When he enters upon her, he should seek permission and he should clear his throat, and he should not approach her upon entering."
حدثنا أبو بكر قال نا إسماعيل بن علية عن يونس عن الحسن انه كان يقول إذا دخل عليها فليستأذن وليتنحنح ولا يقربها بدخول