Females: Are your mouth lips sensitive when aroused?

An old female sub of mine could be very turned on by me gently touching her lips with my finger, circling her mouth, slightly entering her mouth with my finger after a while, and holding my finger across her lips like a bit gag. She would get very aroused almost to the point of orgasm as I progressed. Is this unusual, as have not experienced this effect with other fem subs? Would like to hear from females if this is a turn on for you too.

I’m not a female, but a trans guy. Having my lips touched has never done anything for me.

Well I'll be embarrassed and blushy, but not aroused