What is the ruling on the fiancée placing her hand on her genital organ and moving it for arousal while speaking on the phone with her fiancé, knowing that the marriage contract has been concluded and they will be getting married after four months?

If the marriage contract is valid, it is permissible for you to talk to your fiancée about matters concerning spouses, though it is better to avoid it to prevent arousal. However, it is not permissible for the wife to masturbate with her hand, due to the prohibition of masturbation and the obligation to guard one's chastity except from one's wife or what one's right hand possesses, as Allah Almighty says: "And those who guard their private parts Except from their wives or those their right hands possess, for indeed, they are not to be blamed." It is advisable to hasten to complete the marriage to protect yourselves, for "whoever Allah provides with a righteous wife, He has helped him with half of his religion, so let him fear Allah in the remaining half."