How do i tell him i want ?

he's shy and respects me soo much. we've done evrything apart from and i know he wants it. how do i tell him that i want ? i get so when we play and i know he does two koz i can hear his heart beat real louder and faster when i touch him. i just want to know how to tell him and when? aand how can i talk diirty without sounding like a looser?