Slightly venemous? A snake is either venemous or its not.
Im assuming youre talking about a rearfanged like a hognose... I wouldnt consider handling a mean hognose good practice for something like a black mamba lol. Im not trying to sound like a jerk, im just saying its generally reccommended you gain hours of experience with hots with someone who knows what theyre doing before you get one yourself.