Arm pits go spotty when shaving what am I doing wrong?

If you're only shaving your pits in one directions maybe you're putting too much pressure on them with the razor to get rid of all the hairs. Unlike your legs, your armpit hair grows in several different directions, so for the best shave with the least amount of irritation you should shave up,down, and sideways. Doesn't take long at all. I also use baby oil with aloe to shave my legs and pits since I have extremely sensitive skin. I found that this in combination with the Gillette Venus razor since it also has the aloe strip, seem to cause the least amount of irritation. Good luck!