'I do not want to get into it tonight'
This is reference to a cliched protest users of LSD and similar hallucinogens (including Cannabis) often make with regards to any unnecessary stress or activities they are expected to perform under the influence - "Hey. I am doing the best I can under the circumstances". Those circumstances being of course Cliff's drug impairment.
This notion is along similar lines of 'you are blowing my high' or that attendance to such issues could precipitate a 'bad trip' or some similar psychedelic crises, reinforcing how wasted Cliff is following his evening walk with his special cigarette.