Currently crowdfunding on Indiegogo: the Atomyzer iPhone case. A refillable cartridge on the case holds "60 sprays" of fragrance (or hand sanitizer, or presumably, anything liquid that you want to carry around). Includes a lockable nozzle to avoid accidents.
(found via yahoo)
May be good to put pepper spray in. Can fend off an attacker and then call 911.
Hey, good thinking!