The night I [M]29 got a FJ from my gf’s little sister.

A brief backstory to relate the facts;been in a semi-open yet commited relationship with my girlfriend for 5 years,of which the last we have finally moved in together.Communication is key as always,and mutual honesty has saved us of precarious situations and drama.
When it comes to sex,we have a given set of “rules” for each other and we abide by them to the fullest of our ability.I allow her any sexual interaction with a girl(she identifies as a bi),and anything but intercourse with a guy;in turn she allows me to do anything but intercourse with a girl.
Fast forward to now,her younger sister(she has two sisters of which she is the middle one)is a pretty cool person-we have several common interests and tend to hang out whenever she is in town(goes to college in another city).During the past 3 years,we have shared many things over a blunt or a bottle of beer and even our kinks.
I am a foot guy and she has come to know that from my gf,even made fun of me although she has admitted(amongst other fetishes)that she has tried it and found it kinky as well.Little did I know what would follow the next time she would visit.
Now,my gf was already on vacation with her cousins and I was caught off guard when she stated she would need my hospitality as she would stay in town for a weekend before she went on vacation with her friends,as she wanted to see us(a miscommunication with my gf led her to believe she would be here).
Nonetheless,I welcomed her and we had a chat and some drinks,yet she stated she would go out for the night to catch up with some of her older buddies from college that had moved in to my town of residence(capital city)as she wanted to explore the night;I was pretty tired and in need of relaxation from work and decided to stay in.I gave her an extra pair of keys in case I was asleep when she returned.
She left and so I rolled a blunt,ordered a pizza and sat down to watch some Netflix.At some point,the weed made me horny so I started to jerk off.I likely had the tv on too loud,for I heard her only as she opened the door to the living room at the early hours of the morning.I do not wear underwear when I masturbate and was only in my T-shirt,luckily she was a bit drunk/stoned and as she has long legs she tripped a bit over the edge of the couch(only the light of the tv was on),giving me time to cover myself with a sheet(I turn the AC on anyways for the whole summer)saying that I was a bit cold when she asked me why I was covered when there was hell incarnate outside!
We exchanged a few sentences about her night out,and then she switched into a t-shirt and some shorts and came next to me in the couch,asking for me to roll a new blunt as a welcoming gift.I was pretty anxious(and still hard as a rock!)so I kept my legs crossed the whole time,hoping the joint would put her to sleep.
A few minutes later she was resting her head on the pillows on the other side of the couch,her feet resting against my thigh.I could feel the pump of my heart as we watched the “sexual education”series I had paused on Netflix,and she made a comment about how nasty I was.We had a few fun lines back and forth,though I was as awkward and horny as one can be in a situation like that.
After some time,she was starting to get cold and as I was a bit more relaxed over time,she put her feet under the covers,her soles touching all over my cock and balls,her freshly painted toenails gently scratching them as she was trying to get comfy.I felt cold sweat rushing over me,holding still as eternity itself,but she did not react,still watching the tv.
She stayed there,with her freshly painted toenails until she started to gently scratch my balls and the underside of my shaft while a subtle but sloppy sound was starting to become clear;she was masturbating and I could even smell it.She encircled my cock with her arches,her toes gripping the head that was already lubricated as I was oozing proximity and started rubbing un a circular motion,then pulling down as she started to stare at me;sweaty,in shock and really heavily breathing.
Not even 2 minutes later,I felt my shaft throbbing and I finally turned to her,not caring anymore and uncovering the sight of her feet working wonders on my cock,her fingers buried deep within her shorts and as I did she convulsed violently as she came hard and long,her toes curling literally on my glans and me unloading rope after rope the biggest amount of creamy cum on her toes,soles,arches and even ankles that I have ever shot in my life.
We locked eye to eye after the mess we had made and decided to finish the cigarette and laugh about it,swearing to each other this was to be our dirty secret.Since it would be a one time thing,we indulged in it a bit more later that day,in a sweaty 69 that coated our faces in each other’s juices.
By the gods,probably the most unexpected weekend of my life.(Sorry for the long post)