I say, and with God's success: It is forbidden for the one in i'tikaf to engage in intercourse and its causes; due to His saying, exalted be He: {And do not approach them while you are in i'tikaf in the mosques} Al-Baqarah: 187. If the one in i'tikaf has intercourse below the private parts, or kisses, or touches and then ejaculates, his i'tikaf is invalidated; because it is akin to intercourse. However, if he does not ejaculate, it does not invalidate his i'tikaf; because it is not akin to intercourse. For this reason, it does not invalidate fasting. Refer to: Al-Tabyin 1: 352, Al-Wiqayah p. 245, and Al-Mabsut 3: 123, and God knows best.