All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The practice of oral sex is among the new methods that are used in foreplay. No doubt, sound nature and good sense reprehend it.
Therefore, we advise you to use the other ways of foreplay that are normal and not objectionable.
However, taking pre-seminal fluid in mouth is not permissible since it is impure, even touching it with hand or the like is dislikeable. If it touches the body or clothes, it should be washed away.
Allah knows best.