On the Combo Flexlinks, the needle has a blue head on it, much like a map pin. To be sure of not unsticking/dislodging the cannula before it's had a chance for the adhesive to 'set' - you really need to use both hands. Ditto attaching or detaching the tubing - it has to be level with the plastic bit on the top of the cannula un order to slide on - however they can be rotated through 360 degrees, same one side as the other. Because they slide over the side of the cannula past the little humps and click into place. Then when wanting to remove the tubing for a shower etc, you need to squeeze the sdes of the plastic bit on the end of the tubing to get it back off the little humps, but need to put a finger from your other hand on the other end of the cannula to jeep it firmly attached to you, cos if not squeezed exactly right there will be resistance as you try and slide the tubing catch off.
Much easier to do if you can see!
I have exactly the same prob so eg if Pete's eg cleaning the car or moho so outside for a while, I can't shower at that time. 3 sites either side of my bum, so 12 days in total, so 12 days a month. (2 sites each side of my tum and 3 on each thigh - rest of tum doesn't absorb well at all.)