Oral sex and orgasms

In the past I’ve had two or three encounters with guys trying to give me oral, and for some reason I always stop it after it starts within 2 to 3 minutes because I personally had no pleasure in it.

Recently I’ve been hooking up with a guy and he kind of just go straight in going down between and after we begin to engage in sexual activity.

The question that I have is how long does it take for me to begin to feel the pleasure of receiving oral sex. Should he be down there and licking for 2to 3 minutes before I actually feel a sensation from it , out is it something that just takes time , like 5 minutes? because I feel like I take too long so enjoy it or have the pleasure of it..

Please help !

Sidenote: I don’t think I have ever had orgasm in the eight years that I’ve had sex and I wonder why that is ?

Any Suggestions?