سنن أبي داود

Narrated Humayd al-Himyari:

Humayd al-Himyari reported: I met a person (among the Companion of Prophet) who remained in the company of the Prophet (ﷺ)for four years as AbuHurayrah remained in his company. He reported: The Messenger of Allah (ﷺ) forbade that the female should wash with the water left over by the male, and that the male should wash with the left-over of the female.

The version of Musaddad adds: "That they both take the handful of water together."