Sitting on a futa's lap in a bus~

You stepped into a bus because on this day you were headed to a fancy hotel, you were very excited and rushed to find a seat however there was none available so you went to the very far back of the bus and found a lone woman sitting on one of the seats, when she turned to look at you she immediately hunched over and crossed her legs as if she was hiding something "O-oh! Hi.. Do you... Need somewhere to sit...?" she says blushing, you look and see that there is a seat next to her but it is rather filthy, she catches your look of disgust and speaks up again "Uhm... I don't mind if you... Sit on my lap or anything... D-don't worry, I wouldn't mind if you're heavy or anything hehe.." you raise a brow at the woman, suprised that she'd allow a stranger to sit on her lap but you politely decline which weirdly causes her to look dissapointed "That's... Fine I guess..." now you're even more confused, this lady... Is really REALLY willing to let you sit on her lap... Perhaps she's just that kind? Out of pity you say that you will but only if she's comfortable and that... Completely changes her mood, she looks at you with a delighted smirk "Great! Go right ahead..." you see her posture change as well going from hunched over to upright, you move forward and look away from her until you feel her legs uncross, finally you sit down and onto her lap... Before you could look back at her and ask if she's okay you hear her sigh... The sound of relief washing over her (how in the world was this feeling good to her? A fully grown person putting their weight onto her lap...? Was she really doing this out of kindness...?) either way you try to forget the noise and continue sitting in her lap, nothing else happens for a while until you feel something hard and long against your ass crack, feeling it rub up and down over and over... You slowly look back at the woman and see pure bliss on her face, her eyes closed and that's when it dawns on you... She's... A futanari, that's why she had her legs crossed... To hide a bulge in her shorts... the thing pressing against your ass crack is her hardened dick... Even while it still being in her shorts you can feel every vain and growth around your ass crack, you look away and are now scared... Will you just accept the fate that she might eventually fuck you? Or get up suddenly and make a ruckus? Making everyone look at you both...? All you knew at the moment is that the woman tricked you into acting kind and then using you to get off...

(she starts moaning softly, her dick getting harder in her shorts, pressing more of it against your ass crack as you sit there still on her lap...)