Box of Viagra
We all know the little blue pill and what it does. If your scene calls for the old guy to pop a pill to be able to perform in the bedroom, we have one for him.
This is a prop box, not to actually be taken by the actor. If they need it, they will have to talk to their doctor and not eat our candy props.
Nice touch to have the actor pop a pill and then cut away. It tells the viewer that the couple is having sex without showing it.
Of course you can show it for the gratuitous nudity scene in your movie, just keep it classy. Nobody likes cheesy nudes in low budget productions.