When a male urinates, then proceeds to dab the tip of his penis with a single square of toilet paper or something akin to a baby-wipe.
This ritual is a crude, but slightly considerate, attempt at hygiene when the male is optimistic about receiving fellatio in the near future. Usually occurs when sex appears imminent but the male must excuse himself in order to urinate.
The optimistic dab, while very similar to a full solar-eclipse in the fact that it is rarely seen, only becomes in evident in one of two common situations:
1. The male and his sexual partner reside in the same residence and the aforementioned male fails to know properly operate the bathroom door while urinating
2. When the male is beginning to receive fellatio and the female, while flicking her tongue across the head of his penis, realizes her partner's cock tastes like a wet-nap one receives in a BBQ restaurant. Thanks.
"Why are you wiping instead of shaking? Oh. Wait. Is that an optimistic dab? How cute."
"Darling, your cock tastes like soap. Mind using something other than a wet-nap next time you do an optimistic dab?"