בביאה כיצד אמר לה בפני שני עדים הרי את מקודשת לי בביאה זו ונתייחד עמה בפניהם הרי זו מקודשת אע"ג דחוצפא היא (בין שבא עליה כדרכה בין שלא כדרכה) (טור) ואין דינה אלא כמאורסה ולא כנשואה: הגה וי"א דוקא שבא עליה בבית חמיו אבל כנסה לביתו ובא עליה או שקידשה כבר ובא עליה דינה כנשואה י"א דפנוי הבא על הפנויה לפני עדים חוששין שמא כוון לשם קידושין (מרדכי פ' האומר) דחזקה אין אדם עושה בעילתו בעילת זנות אבל אם כבר הוחזק לזנות או שיש לו אשה אחרת לא חיישינן (ת"ה סי' ר"ט) ויש מקילין בכל ענין וע"ל סימן קמ"ט וקס"ז סעיף ב' ולעיל סימן ט"ו סעיף י':

With sex, how? He said to her before two witnesses: "Behold you are married to me with this sex," and he secludes himself with her before two witnesses, behold she is betrothed (even though she is bold.) Either he has sex with her in the normative fashion or he has sex with her in the non-normative fashion. And her status is only as someone who is engaged, not like a married woman. Ram"a: There are those who say that it is precisely when he has sex with her in the house of his father-in-law, but if he brought her into his own house and had sex with her, or betrothed her already and had sex with her, she is considered like a married woman. There are those who say that a single man who has sex with a single woman before witnesses, we suspect that he intends [this act] for the sake of marriage, and the presumption is that a man does not have promiscuous sex. But if he is already presumed towards promiscuity, or that he has another wife, we are not concerned. There are those who are lenient in this matter.

The one who marries a woman with sex, his intention [is fulfilled] upon finishing the sexual act. Therefore, if before he finished she received kiddushin from another, she is married to the second [person]. But if he was stimulated in her, and leaves immediately, or when he said before that his intention to acquire upon being stimulated, he acquires immediately.