Hair is not the best place to spray anything containing A1 as it can quickly break down to none, leading to buildup/smelly problems - none also has an affinity for hair and binds strongly, this needs a good long hard scrub with soap and water to remove.
Depending on length/volume, hair also may not be the best surface for diffusion - somewhere with good blood flow and access to air is usually your best bet. Similarly, none itself and other pheros that break down to none eg nols, should be kept away from hair for the same reason.
This thread pretty-much says it all for application points:
Applying over a little lotion also helps slow breakdown and prolong activity.
Any decent cologne that sits well with the IFM scent can be used as a cover - leave a minute or two between applications so each layer dries down or apply them adjacent to each other.
Situations - Have a read of these threads. Loads of info on using A1 effectively here:
Although you can still discuss/post about A1 here, AD has stopped using it, so reports on A1 or any mixes using it no longer count towards RU status.