Tantra is a system of technique and physical practice—we stress physical practice—combined with certain metaphysical assumptions about the world that can be proven through personal experience but not necessarily via rigorous scientific examination.
They don't entail moral doctrine, save in an esoteric sense; they don't entail personal restrictions; and they don't include concerns of good and evil aside from the aspirant's advancement.
Tantra is essentially a combination of practice and philosophy aiming at the ultimate development of the practitioner into his greatest form. You may take this approach in whatever direction you want, whether it's dealing with afterlife beliefs or personal power in the actual world.
You may also want to read more about Tantra Yoga here.
