Well, I have now tried both the IS/a and the IS/b separately. Both have a clear effect on me in terms of self effect which I found quite surprising. I thought I was supposed to be either an IS/a or an IS/b girl… (or was that TAH or TAL) 
Anyways… here’s what I noticed when using IS/a and IS/b;
IS/a (1 spray between wrists, 1 spray to the chest)
The self effect was quite dramatic and quick, I noticed it after just a few minutes. I was more smily and chatty than I usually am. In terms of sexiness it was a very energetic and confident flirty sexy feeling, I just felt like “come jump me right now”
IS/b (1 spray between wrists, 1 spray to the chest)
This one had a definitive effect as well, but not at all like IS/a, very much less energetic. It was more of a slow, sultry & seductive sexiness… a “I feel like burlesque dancing or doing a slow striptease before getting down and dirty with you”.
I guess they really did fit the descriptions used here LOL It’s definitively a big difference between Angelina Joli & Marilyn Monroe 
Im just surprised I reacted to both! And as much as I liked the thrill of the IS/a effect on me, I felt a bit like I do when I get smashed…it just wasn’t quite me. My personality fits better with IS/b, I felt a lot more like myself with that one.
Bottom line I suppose…I’ll wait and see which one my TG reacts best too and then have that one as my staple Fingers crossed one of the IS potions will work its magic and help me snag him