The Prophet (May peace be upon him) said : When any of you has intercourse with his wife and desire to repeat it, he should perform ablution between them. (Using translation from Abū Dāʾūd 220)
"إذا أتى أحَدُكمُ أهلَه ثم أراد أن يعودَ فليتوضَّأُ بينهما" .