I wish if i could lick the pussy of my girlfriend,

I wish if i could lick the pussy of my girlfriend, she asked me to do it alot of times but I refuse the problem is that i think this area (the pussy in general) is meant for one thing, for a cock (mine) to be inserted in it, which i always do but putting my tounge there and start licking? yakkkk!! this place is so wet and full of humidity and oozes alot of secretions (like a precum) how would I lick it? it's not healthy at all i think i will die if i did this, or even get some kind of a disease in my mouth and tounge