Within moments, you feel intensely turned on. Your brain fills with thoughts of hot girls (and, weirdly, a few guys- you didn't think you were into them) and your cock rapidly swells and gets hard.
Noticing this, the scientist gently pushes you down to lie on a table, and two attractive nurses, one man and one woman, come in to pull off your pants and underwear. You blush a bit as they see your hard cock, but then they position it to go inside The Tube, and you feel it slide into place.
The Tube is intoxicating. You feel your hips thrusting you towards it and pant uncontrollably as you push inside it. Being in its tight, sensual grip is just like fucking a pussy. It moves back and forth against your hips as you try to push inside it.
When you're about to cum, it clenches your shaft tightly, and an invisible layer to it tenderly rubs your head as you touch it. And with an eager moan, you cum inside it. Your cock pulses as it squirts semen inside The Tube, the white liquid seeming to flow for hours as The Tube sucks up more and more of it, and you wonder if you'll ever stop cumming.
Eventually, you do. The Tube slides off your shaft, and you pant, feeling as if every drop of your cum has been shot into it. "How was that?" the scientist asks. You pant eagerly in reply. "Good, because there's more to come," he smiles.