It was narrated that Abu Sa'eed said:
"The Messenger of Allah said: 'If anyone of you has intercourse with his wife, then he wants to do it again, let him perform ablution.'" (JA)
English reference (JA): Vol. 1, Book 1, Hadith 587 (JA)
Arabic reference (JA): Book 1, Hadith 630 (JA)