It was commented on by Len that Dom is staring at Lilia's bum, but I've noticed that a lot of their routines involve Dom grabbing hold of Lilia's bum.

Now since Lilia choreographs the routine, I can only assume that she must like having her bum grabbed.

If so, how do I apply for the job?

No, Lilia just likes to win and feels such cheeky routine suits Dom... Not that I agree with her about the routine, but she did make Dom seemed like a decent ballroom dancer!