Abu Ubaydah says: Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him) said: A man should perform ablution after skin-to-skin contact, after touching with his hand, and after a kiss (that is, when a man kisses his wife). And he would say about the verse "or you have touched women": It refers to ghamz (pressing with the hand).
Al-Tabarani recorded it in al-Mu'jam al-Kabir; Abu Ubaydah did not hear from his father (Sayyiduna Abdullah bin Mas'ud).
Hadith Referenceمجمع الزوائد ومنبع الفوائد / كتاب الطهارة / 1283