this is a question for someone
I am asking on behalf

what is the Shia ruling on sexual fantasy example
can husband and wife discuss sex and talk about their past and what they like and may be talk about others but it will remain with them only .

also in oral sex is licking and sucking allowed.

sorry to ask you these type of questions
but it could save some body from GUNAAH

It's not allowed in Islam to discuss about other people sins also it's not allowed to discuss about the sins which you made in the past.
Oral sex is allowed but it's makrooh. Specially if your wife don't want it