Sunan an-Nasa'i, Book 1, Hadith 264 (In-Book) ⓘ
It was narrated from Abu Sa'eed that the Prophet said: "When any one of you a wants to return (to have intercourse again), let him perform Wudu'."
أَخْبَرَنَا الْحُسَيْنُ بْنُ حُرَيْثٍ، قَالَ حَدَّثَنَا سُفْيَانُ، عَنْ عَاصِمٍ، عَنْ أَبِي الْمُتَوَكِّلِ، عَنْ أَبِي سَعِيدٍ، عَنِ النَّبِيِّ صلى الله عليه وسلم قَالَ " إِذَا أَرَادَ أَحَدُكُمْ أَنْ يَعُودَ تَوَضَّأَ " .
also referenced under: Volume 1, Book 1, Hadith 263 (DarusSalam)