He's gaming and distracted, and I'm sat slightly behind him on an armchair. I have a blanket on my lap and extremely loose trousers on. Underneath, my cunt is stuffed with a tentacle dildo that is 7,5cm thick at its thickest. I snuck into the bathroom with it and played with myself until I almost came, then slid it in, pulled up my panties really high to keep it in place, and then put on my big trousers to hide what I'm packing until I sit down.
I'm sat sideways across the armchair, with my legs over the armrest, so I can push against the side slowly massaging the dildo deeper and deeper inside me. I think if I snuck a touch to my clit I'd cum immediately. I'm trying so hard not to wiggle my hips too much so that it's obvious that I'm masturbating. I can feel it slowly slide deeper and it's making me ache being so full I'm absolutely at capacity. I'm almost at the base and the idea of it fully slipping inside drives me wild, but it's too long for that. I'm so fucking wet and horny.
UPDATE: I had a huge orgasm and it wasn't noticed, mission successful