In any case, don't let embarrassment become a health risk. The following script may give you some ideas. A condom, sweetheart. But we've never used a condom before. Getting AIDS is totally gross.
People carry STIs without knowing it.
You can get STIs from pre-cum, too. Making love with a rubber on is like taking a shower with a raincoat on. Doing it without a rubber isn't making love it's playing Russian roulette. But I love you. Just this once without it.