You Have A GirlFriend...

What I would do is this:

I start to cuddle her to assuage her anxiety and fears. Then I start the foreplay; a lick on the neck, massaging her breasts, adds a light kiss and slowly progress into a deep kiss, etc. etc. I remove her clothes and mine, and then when we move beyond simple foreplay, I take the ropes and gags from underneath the bed and start tying her up, all the while convincing her that bondage is the best form of love there is. I gently tie a scarf over her eyes to heighten her senses as I start the bondage. Slowly, I tie her wrists together with rope tied with a cinch knot. I progress onto tying her breasts above and below and securely lash her arms together, and as I do this, I gently breath onto her ear and get her to be more stimulated as she cannot see but feel and hear, feel the ropes holding her together like a warm embrace, hearing my breath and hers mingling. I move on to her lower body and tie the famous crotch rope. "Ahn!" The rope bites into her already stimulated clitoris and neatly bisecting her labia. She cannot see, but she can feel the rope riding its way into her pussy. I take the blindfold off, and gently walk her over to the mirror where she glimpses at her bound, nude self, boobs protruding due to the rope accentuating her B-size breasts. "How do you like yourself? All neatly tied and trussed up, and can't do a thing to stop me," I say but I give her a gentle kiss that belies my sadistic tone of voice. By now, my penis is a-raging, and she feels my dick against her ass, and she blushes, "You..." I chuckle, and bring her back to the bed as I grab her panties and with a deft move stuff it into her mouth and I secure it with another piece of cloth by way of a cleave-gag. Her eyes widen in surprise, but she can't do anything to stop me, and she realizes that I mean nothing but love for her. I take the scarf used to blindfold her and tie an over-the-mouth gag over the cleave-gag. She tries to say something, but all that comes out was a soft, "Mnnn!" At this point, the beast inside of me explodes, and I move in and start my sexual attack. I lay her back onto the bed and I lick her clit, I grope her breasts, and I'm touching her every part in reach. While I administer my sexual attack, her love juice starts dripping onto the bed, which indicates to me that she is more than ready to accept my cock. I take her missionary style, and grab her legs with my arms to clear her crotch... the moment of truth. I stick my dick into her pussy, and I further penetrate her until I reached the end of my dick. She moaned in pleasure, not pain, through her gag all the way. Like a vacuum, it sucked my dick, and I began the last act. Rhythmically, I push and pull my dick until I could comfortably maneuver my dick in her vagina. Getting at that, I up the tempo, and I start going faster and faster, me grunting and her moaning. In and out, in and out, I was slowly reaching my limit; her pussy was so damn good! Nearing my climax, and hers as well through her increasing loud moaning, "I'm going to cum, I'm going to cum!" "Mnnnnnm!" And then there, I felt my control slip and out forth my dick came white hot semen that gave me ecstasy. At the same time, she closed her eyes and arched her back, her feet curling, and she emits her loudest, sexiest moan through her layered gag. Spent, and exhausted, I collapse to her side and as I pull my dick out, our love juices flowed out of her pussy, making a neat, wet circle on the bed sheets. I ungag her and take the sodden panties out and ask, "How was your first bondage experience?" "..." She looks at me, but no words escape her mouth to express her feelings. Instead, she leans over and kisses me, taking me by surprise. I look at her, and take her into my strong arms and hug her and thought no more but happiness.
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Clearly my imagination and bondage enthusiasm got the better of me. I must've wrote this in 8-15 minutes.