I'd also use a separate follow button. Build /assist into your attack macros and leave it out of non-attack macros. Especially with Shaman, you can multitask your follow button with other things. I use :

/click [nomounted] SmartBuff_KeyButton
/cast [nomounted, nocombat] Totemic Recall
/focus Kina
/follow focus

If I'm not mounted, it will set my main as my focus target, follow my focus target, recall my totems and refresh any expired/expiring buffs.

If I'm mounted, it will it will only set and follow my focus {so as not to fall 4000 feet to my death via buffing related dismounting}.