How can I get over my shyness?

My boyfriend and I have kissed lots before... but I still can't bring myself to be so confident as to kiss him myself... for example, last night he was being cheeky and asked me to prove my love for him and I just froze. I can't get over my shyness... he kisses me on the cheeks and forehead and hands and shoulders lots because I think he senses my apprehension... I really do love him but I don't know how to do what I wanna do!