You secrete a toxic venom of a particular type. There are many types of poisons. When you bye this power, you get one poison effect and one delivery method. Your repertoire of either can be increased with extra schticks.
Use the Poison rules, with your Powers as the strength of the poison.
Blood
Your blood is poisonous. By inflicting a Wound Point on yourself, you can poison a weapon, so that it will poison anyone it wounds in the next fight. Anyone drinking your blood is poisoned as under Gland, but it is real hard to fool someone into drinking your blood.
Gland
You can milk a gland in one of your extremities to produce a poison which must be ingested to take effect. It is quite difficult to notice this poison. Use all the rules for non combat poisons.
Lips
Your kiss is lethal. A kiss, or prolonged contact with skin, will transmit the venom. This poison is very hard to use in combat, but there is also no obvious sign of it. Otherwise use the same rules as for Gland, above.
Spines
You have long cobra-like fangs, hollow spikes or some other protrusion to inject your target's body with venom. If you have Abysmal Spines or Tentacles, they can be your method of injection. You must damage your opponent, causing at lest one Wound Point.