If the insemination (having kids) is not vital for both of you, then it is not permissible, neither in Ramadan, nor in other months.
There are two points here:
1- You will do the Masturbation with your own hand, which is haram.
2- You will practice in front of other people, which is also haram.
Can not you ask them to give you a container, where you can pour the semen in at home, and take it to them immediately?