I say, and with God's success: It is obligatory to perform Ghusl (ritual washing); because the condition for the obligation of Ghusl upon ejaculation is the separation of semen from its place and resting place — which is the spine in men and the bones of the chest in women — due to desire. Thus, the condition is fulfilled, and Ghusl becomes obligatory; because what matters is the separation, not the exit. See: Rad al-Muhtar 1: 108, Al-Wiqayah p. 94, Al-Sayah 1: 310, Al-Hidayah 1: 17, Al-Ikhtiyar 1: 20, Al-Kanz p. 4, Al-Multaqa p. 4, Mukhtasar Al-Quduri p. 3, and God knows best.