Hello Balava. Best thing would be to test the application and ask someone if it can be perceived. I myself apply 1 spray to the neck and 3 to the body (1 sternum, 1 middle of the chest, 1 belly). It gets weak over time - that's why I often spray twice to the neck and twice to the sternum -, however, many people here say others can smell it even when you think it's gone.
I wouldn't advice you to spray it onto the armpits. The fragrance would mix with sweat immediately, and from my experience that's no good. If I want to cover sweat I spray onto the shoulders or to the sides of the body, between armpits and hips (don't know the English terms for that).
So, nice to have you here, and take care, too!