Try inviting a good mate and his "not shy" girlfriend,who are mutual friends to you both, round to your place. Plenty wine, then have your pre-asked mate take his girl to bed in the next room to you,on the pretext they are tired. You follow and , in bed next to your girlfriend,she then hears the sounds of sex with lots of loud moaning,lots of sexual language,now try kissing her, starting at her tits then work your way down, keep on circling her clit with your tongue while she is listening to another female getting the same,try and get her fully aroused in time for her to hear the other girl start shouting things like ohh fucking hell don't stop, faster, faster then she will know the other girl is close to orgasm,now concentrate your tongue running it as fast as you can over and over on her clit, then finally you will both hear the sound of loud screams of female orgasm, keep going, if she hasn't come it may be she NEEDS a cock,and she'll want it in fast and you'll need to give her a good fast hammering, this should take her past the point of no return. Let me know how you get on

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Sex is good.
But nothing beats the build up.