(R. Ba bar Chiyah citing R. Yochanan): Entrance of the crown is full Bi'ah! (Rather, R. Yochanan must hold like Rav and Shmuel.)

Question: What is the case (for which R. Yochanan said that this is full Bi'ah)?

Suggestion: It is for all other Arayos.

Rejection: [For them,] the Torah made Ha'ara'ah like full [Bi'ah]!

Suggestion: It is for Shifchah Charufah [about which it says "Shichvas Zera"].

Rejection: [For Shifchah Charufah, he is not liable] until he ejaculates, like R. Yirmeyah cited R. Ba bar Mamal citing Rav, "Shichvas Zera" - until he ejaculates!

Answer: Rather, the case is, a widow to a Kohen Gadol;

(R. Ba bar Mamal): Once he did Ha'ara'ah, he is liable for Bi'ah. Once the crown enters, he is liable for her due to Chalalah. When he finished his Bi'ah and ejaculated, he is liable for "v'Lo Yechalel Zar'o b'Amav." (We explained this like SHIREI KORBAN.)

(Mishnah): All women become Tamei [when blood goes to] Beis ha'Chitzon.

Question: What is Beis ha'Chitzon?

Answer #1 (R. Yochanan): It is until the place that is visible when girls sit (and open their legs) to urinate.

Objection (Reish Lakish): All Tum'os that are Metamei [through touching], there they are Metamei! (This shows that it is considered external. We know that a woman becomes Tamei when the blood is "bi'Vsarah" (Vayikra 15:19), i.e. inside her!)

Answer #2 (Reish Lakish): Rather, it is until Beis ha'Shinayim (a place in the womb with strands of flesh with a semblance to teeth).

(R. Zakai - Beraisa): It is until Beis ha'Shinayim, and from Bein ha'Shinayim (between the 'teeth') and inside, [blood is not Metamei].

Answer #3 (R. Yosi bar R. Bun citing Shmuel): The entire Beis ha'Ervah is called Beis ha'Chitzon. (It seems that this is brought here, for until this place is full Bi'ah.)