Musannaf Ibn Abi Shayba 1:1726

Ibn ‘Ulayyah narrated to us, from Salamah ibn ‘Alqamah, from Ibn Sirin, who said: I asked ‘Ubaydah about the saying of the Exalted, "Or you have touched women," and he gestured with his hand. I thought I understood what he meant, so I did not ask him. He said: And I was informed that Ibn ‘Umar, when he touched his private part, would perform ablution. Muhammad said: I thought that the statement of Ibn ‘Umar and the statement of ‘Ubaydah were one and the same thing.