Something

/obj/item/weapon/reagent_containers/food/snacks
	proc
		foodloc(var/mob/M, var/obj/item/O)
			var/turf/spawnloc
			if(O.loc == M) return M.loc
			else return O.loc


and then

var/turf/spawnloc
spawnloc = foodloc(user, src)