Distinguish the term only the first time. It would be unnecessary to let one word stand out multiple times and it may remove the distinction altogether, depending on how often your glossary terms occur in your text.
Normally, blood circulates into your penis through the arteries, and out again through the veins. When you are sexually stimulated, tiny muscle rings around the veins contract, which prevents the...
This is even less likely than an ordinary zombie outbreak. If it happens, however, regardless of gender, you should establish a safe zone (or "base") stocked with food, supplies, and...