The Messenger of Allah ﷺ said, "No one should sit between two men except with their permission."
حدثنا محمد بن عبيد وأحمد بن عبدة المعنى قالا حدثنا حماد حدثنا عامر الأحول عن عمرو بن شعيب قال
أن رسول الله ﷺ قال لا يجلس بين رجلين إلا بإذنهما
No references are available.
[Its chain is hasan] Tirmidhi narrated it in the Book of Manners, Chapter on the Dislike of Sitting Between Two Men Without Their Permission, no. 2752, from the hadith of Amir Ahwal, transmitted through him. See also the following hadith.