How should i do it... i have

thats what the pipe looks like..how can i rig up the o2 sensor to make it work??? or should i find a way to weld a bung into it..???

 

I wouldn't weld a second bung in there because you'll most likely just wrap the sensor in tinfoil as this seems to be the favorite thing around here, and tuck it out of the way. I doubt you're going to want to put the sensor back in the exhaust stream w/o a cat.