so I was thinking of using sometuth with...

my favorite cologne. Not mixing them together but using them on seperate part of the skin.
for example, spray 1 shot of tuth behind each ear(my sweet spot), and spray my cologne on my chest or wrist or even clothes) for clubbing
would spraying cologne take away or minimize the effectiveness of tuth eventhough they have NOT been sprayed on the same spot?

No, not at all. You can even spray the cologne directly over any phero application points after allowing them to dry down, without reducing the effect.