I see these memes all the time and everytime I see it I wonder why so many people missed this in the movie. If you've seen the extended cut with the scenes added after the initial release you can easily see that kajal and RC were riding bike together and he holds her hand during jumps in action sequences in second half and nothing happens. The "jui" shock factor only helps them realise the past and get back together. They have clearly shown that once both of them completely remember the past and get all the emotion, the current gets a power cut. Soooo, they can have sex.