TMI! Preseed

I got Preseed to try out this month. I know it says to put it in about 15 minutes before intercourse. My plan was to keep things spontaneous and put it in without my boyfriend seeing me do it and then come in and initiate sex. But sometimes he likes to go down on me, would that be gross with the lube in there? Does it leak out and will he taste it? Is that even okay to do? Lol