Tilt your pelvis just a little

Alex continued to saw his cock between your pussy lips, dragging deliciously against your clit. Several more times, you felt him pull back far enough for the tip of his dick to graze against your opening. Each time, a slight thrill coursed through your body. If either of you were to change your angle even slightly, this would turn into much more than just dry humping. Your pelvis tilted slightly, as if it had a mind of its own.

As Alex kept thrusting, his dick caught in your opening several times. You were tantalizingly close to having sex at this point. Just a little further...

Alex's dick slid inside you with one swift motion. You moaned out in pleasure, but Alex kept thrusting a few times before he noticed exactly what happened. "Oh," he sighed and paused, fully embedded inside of you.

He stayed that way for a moment before asking, "Should I...?" He didn't bother finishing the sentence. It hung there for a few seconds before you responded.