Is it the start, can't say. Vinni saw them in full action, she is a teenager, who knows that her brother has sexual desires for her. How can she control herself from lurking, if someone is indulged in a passionate sex just beside her room, and if one of the member is her brother, makes it more interesting.
Well vinay confirmed that vini saw them, due to the footsteps, something is cooking inside his mind which is definetely gonna be interesting, beware vinni, your brother is coming. Somewhere her desires are also the same as vinay but the thing is she refused him from any further innuendo, will not be easy for her to submit to his lustful desires.