al-Qasim ibn Muhammad القاسم بن محمد بن أبي بكر الصديق · The Book on Purification

"When the circumcised meets the circumcised, then indeed Ghusl is required. Myself and Allah's Messenger did that, so we performed Ghusl."

"The Prophet was asked about a man who finds wetness and he does not remember having a wet dream. So he said: 'He is to perform Ghusl. And (he was asked) about a man who had a wet dream but does not find any wetness, so he said: 'No Ghusl is required of him.' Umm Salamah said: 'O Messenger of Allah! Is the woman required to perform Ghusl if she sees that?' He replied: 'Yes. Indeed women are the partners…

"Allah's Messenger said to me: 'Bring me the Khumrah from the Masjid.' She said: "I said: 'I am menstruating.' He said: 'Indeed your menstruation is not in your hand.'"