Mahāsaṅghika Vinaya
Bhikkhunī Pakiṇṇaka
Pakiṇṇaka 1
Beginning of the explanation of the collection of miscellaneous rules.
The rule on sitting
The Buddha was staying at Sāvatthī. At that time, a bhikkhunī, in the early and late parts of the night, sat down in lotus position. Then a snake came and entered her vagina. The bhikkhunīs told Mahāpajāpatī and she for this reason went and informed the World-honored One. The Buddha said: “You should give her such-and-such a medicine. The snake won’t die, but come out again.” Then they gave her the medicine, and it came out. The Buddha said: “Why did you sit down in lotus position? From now on, it’s no longer allowed. The method to sit is to bend one foot, and to cover the vagina with the heel of the other foot.” If a bhikkhunī sits down in lotus position, she breaks a minor vinaya rule.