Speaking from experience. You need to always start north and work your way south. Start with deep passionate kisses as you gently caress her breast taking her nipples between your thumb and forefinger gently roll around. Then run you tongue all around the nipple as it becomes erect. The nipples have a direct nerve running down to the pussy. Start with the nipples and the pussy will be longing for your touch. Never be in a hurry. Take your time teasing her with your tongue. If her panties are still on, nibble on her through her panties and then gently slide them away from her pussy lips and tease and tantalize with your tongue. If she is truly enjoying this you will know by her moans of pleasure. Have her completely begging you to enter her before you fuck her with your tongue and then slide a couple of fingers in and finger fuck her as you lick her. This has made me have mutiple orgasms.