<human>: Can you give me the gist of the text in a nutshell?

Hi! First time posting here - hope this is the right place for my question.
Backstory:

1) Met Girl on Tinder (note: Tinder is being used very differently here - it's not just hookups. Very rarely actually)

2) Went for drinks - was fun

3) Met again a couple of days later at my place - fooled around (no sex)

4) Two days later: Went to her place (only for 2 hours - we both had other plans later but could make some free time for each other), it started to get frisky. She told me she's on her period. She gives me a blowjob, I tell her I will make it up to her the next time we meet (which I will - I love going down on girls)

Now I think this girl is really cool and it's fun to hang around with her - but I only want sex. She started to text me after last night, even sent me a picture of her having a good time and teased me about not being there with her (I wasn't interested - plus I was too tired).

I want to tell her that I'm only interested in having sex with her - I'm not looking for anything serious (at least not with her) - we haven't talked about that yet. Problem is I feel she might be thinking we're dating (which technically we probably are...I think I screwed up here)

Now I don't want her to feel I've just "used her" for a blowjob - I will totally make it up to her and rock her world: But I feel I need to be totally straight with her before doing so.
<bot>: How should I tell a girl I just want sex (if I suspect she might be into me) without sounding like a dick?