Why should you not tell a woman how many women you’ve slept with? How should you answer instead?

I was asked this question by a girl I was in bed with tonight. She seemed just genuinely curious, not like she was trying to catch me out.

I’ve often seen in the seduction community that answering this question honestly is considered to have detrimental effects (of which I’m unsure). This instinctively makes sense to me but I haven’t thought through exactly why.

I would like to hear any and all wisdom people have regarding this, and if you have a preferred response feel free to share.