First up, remember that the sextile in transits is a 3rd and 11th house aspect. It has connotations with associations with groups (11th), contact with the immediate surroundings and how you integrate with them (3rd).
That is probably why in a Jupiter sextile Mars transit, your actions are likely to be well-received by others and you don’t ruffle their feathers, unlike Jupiter square Mars where there’s potential for annoying those in authority (square is a 10th house aspect) or Jupiter opposition Mars (7th house aspect) where you could get on the nerves of another people.
Focusing on the sextile, there’s confidence and optimism in your actions. You can act with ease on your plans and long-term aspirations. There’s easy flow of energy and action to actualize your vision. Certainly, with sextiles and Jupiter transits, those opportunities need to be taken up and acted on. But with Mars involved here, that’s usually not an issue.
Mars also represents the physical vitality and drive. You tend to enjoy unusually good health and physical energy during this time. Different sources claim that this is a great time for giving birth as well. Naturally, it’s great for sex too. Especially if there’s any inhibitions involved. Jupiter will just cast them aside!