Kylie Jenner Heating Up ... with Lil Twist

7/4/2013 9:30 AM PDT

Kylie Jenner -- Heating Up with Lil Twist

15-year-old Kylie Jenner is playing the field -- just a week after hitting up a movie with Will Smith's son Jaden, things got SO HOT between her and Justin Bieber's friend Lil Twist ... they had to cool off with frozen yogurt.

While Jaden was out doing his own thing, Kylie and Twist got together yesterday in West Hollywood for some Pinkberry ... A WELL-KNOWN APHRODISIAC!!!

Funny, Twist has a terrible track record behind the wheel of Bieber's cars -- example 1, example 2, example 3 -- but for some reason, Kylie still let him drive her around.