Ibn Umar (may Allah be pleased with them both) said: I have not abandoned touching these two corners, the Yamani Corner and the Black Stone, since I saw the Messenger of Allah (peace and blessings be upon him) touching them, neither in ease nor in hardship.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9233
Ibn Umar (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) used to touch the Yamani Corner and the Black Corner in every circuit, and not the other two.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9234
Jabir bin Abdullah (may Allah be pleased with them both) said that the Messenger of Allah (peace and blessings be upon him) touched the Black Stone and kissed it, and touched the Yamani Corner and kissed his hand.
Umar bin Qays al-Makki is da'if (weak). A report has also been narrated about kissing it (the Yamani Corner) that is likewise not established.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9235
Ibn Abbas (may Allah be pleased with them both) said: Whenever the Messenger of Allah (peace and blessings be upon him) touched the Yamani Corner, he would kiss it and place his right cheek on it.
Only Abdullah bin Muslim bin Hurmuz narrated it, and he is da'if (weak). The reports from Ibn Abbas concern kissing the Black Stone and prostrating on it, unless by the Yamani Corner he meant the Black Stone, for it too is called by that name, in which case it agrees with the other reports.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الحج / 9236