Just because it looks like your ex's, and in the sack you could make your ex come back to back to back, that doesn't mean shit when your with somebody else. Don't assume anything here, it's best if you walk into every new oral situation as if it was your first, regardless of how studly you may have been in the past. If the way you made your last come doesn't work on the one you're with now then WORK ON IT! Anything good is worth time and effort being invested, right? :)