We had the opportunity to experiment further a couple of weeks ago, and I have to say the results were rather encouraging
I applied generous amounts of cream three times during hand spanking, which elicited some very satisfactory whimpering and fidgeting for an hour or so. The heat and burning sensation lasted the rest of the day - in her bottom as well as in my hand!
The only problem appeared afterwards at night - even though she washed carefully with first olive oil and then soap before bedtime, apparently some of the capsaicin remained. With a little bit of sweating it was transported to rather more sensitive areas, giving her a hard time sleeping. We'll have to work on that bit I guess
To me nettles, capsaicin and similar "implements" are emotionally very powerful due to their inescapability. Once applied there's nothing you can do but accept and endure - often for rather a long while! That puts them a very special place in my heart.
Oh, by the way, it really can be very difficult to get off, even using olive oil. If you ever find yourself applying capsaicin to a young lady's bottom, try to remember not to touch your eyes with that hand for the rest of the day...