Under ARNIE or HARRY Armpits is card number 597a/597b of Old Series 15.
The sticker depicts a rather unsavory-looking fellow on a blind date. He presents the young woman with a flower bouquet he has growing out of one of his armpits instead of hair, and she makes a face in disgust
A sendup of the convention portrayed in works of entertainment of how single people are often fixed up on blind dates with unpleasant and/or unattractive partners. Also, name a is a pun on "underarm" and name b is a pun on "hairy armpits".