Here is the story. 

My company needed some things approved from a city office. These two guys sat down with me and my business partner to look over everything. Both of them were being extra friendly towards me.  One in particular. Now being professional I couldn't really do much about it. He gave me his work card at the end of the meeting. When I went to hand him my card (including my cell number) I realized I had run out! Fast forward. We get approved yesterday and are at this meeting. My original plan was to go talk to him then and give him my number and just give it a shot. BUT my partners walked out of the meeting once our business is done because we had another meeting after across town. 

The question. Do I just let it go or should I email him something friendly saying thank you and include my number in the signature line?

If you think I should email him what should I say exactly. I want to remain as professional as possible while also saying "hey cutie. Text me" lol

I've never flirted in a professional aspect let alone through email so I thought my <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> sisters could help me out!