Cycling drug cheats…

Can someone please tell me, how do they do the blood transfusion? Why doesn’t the bruising appear around the needles puncture wound? I thought riders shared rooms? I am at a complete loss as to how this kind of drug taking happens, Yeah offer them the threat of getting up during the night as it will keep these ‘Scum’ of our great sport nervous=absolutely, if they dont take drugs then they wont loose sleep. If guilty the UCI etc. should ban him, the Tour de France winner (Contador) for life and stop being so annoyingly soft…