In the view of Sayyiduna Abdullah bin Mas'ud (may Allah be pleased with him), a man should perform ablution (wudu) after intimate contact (mubasharah), after touching with his hand, and after kissing his wife. And he used to say concerning this verse, "Or you have touched women" [Surah al-Nisa': 43]: "It means touching with the hand."
Hadith Referenceالمعجم الكبير للطبراني / باب العين / 9194