Showing intention is definitely needed, otherwise you will probably be in the friendzone. Overtly showing it is very simple, by just saying that you want sex if you just want sex. However, many advice said that covertly showing it is sexier and the girl will perceive you as socially competent person and I totally agree. I did it both ways before that the covert way was better; it was fun sexy and artful. The problem is, I have to wait for an opportunity, wait for her to say something that I can use. I have no clue how to create that opportunity myself but I am sure many guys know how, so if you have anything to share (advices, tips or story) please tell me, thanks