WASHINGTON (AP) _ The question to President Clinton was pointed and probing: Why DID he put that AstroTurf in the back of his pickup?

Don Imus, the raucous New York radio personality, referred Thursday to Clinton's reminiscing last week about having an El Camino pickup in the 1970s with the bed lined with AstroTurf.

In a telephone interview that veered wildly from the serious to the silly, Clinton gamely explained that he had spruced up the bed of his ''Cowboy Cadillac'' because he hauled luggage in it.

''It wasn't for what everyone thought it was for when I made the comment, I'll tell you that,'' he insisted. ''I'm guilty of a lot of things, but I didn't ever do THAT.''

Imus gently chided Clinton with a reference to the president's campaign- days disclaimer that he had tried marijuana but not inhaled.

''That's like saying you didn't inhale, Mr. President,'' he said.

''No, it's just that I didn't inhale in the back of a pickup,'' Clinton shot back.

The exchange was part of Imus' second interview of Clinton as president after having him on as a regular guest during the presidential campaign.

Professing new deference now that Clinton is president, the host of WFAN- AM's ''Imus in the Morning'' promised early on that there would be no goofy questions. He was just kidding.

Between questions about weighty matters like Bosnia and trade, Imus took off on Clinton's eating habits. He reminded the president that earlier in the week he had downed double lunches in Ohio, including a ''Clinton burger and that pastrami sandwich and that apple fritter the size of a baby's head.''

''Hey, hey, the apple fritter - I had one bite 3/8'' Clinton protested.

Then, the president seemed to assign his eating binge to forces beyond his control.

''I did get off my diet that day,'' he allowed. ''But I was transported. I mean, I was out there in a place I felt at home in. I was in a little town in Ohio, you know.''

Adding a populist flair to his long-winded explanation, he added, ''I stopped at this little deli with this guy who had been a butcher's assistant when he was 13 years old and had finally saved enough money to open his own deli three years ago. And he built it with his hands, and he made this Clinton burger. And I thought, well, I'm, going to eat it.''

Clinton tried the same Everyman touch again when Imus derided the model home built as part of the failed Whitewater real estate venture the president had invested in during the 1980s.

''I don't mean to be disrespectful,'' Imus began, ''But that ... model home looked like someplace where Tonya Harding's bodyguards were holed up. No wonder you guys couldn't sell them.''

Clinton replied, ''It was a little place where a lot of working people without much money were looking for a place to retire and own some property in a beautiful place.''

Then, in a gibe at Imus, he continued: ''I know that now that you've hit the big time, it's not worthy of you.''

Clinton did seem to jump at one of Imus' suggestions: that the president and first lady go on TV's ''American Gladiators'' to tackle Harry and Louise, the actors who criticize the president's insurance plan in TV ads financed by the insurance industry.

''You know, I wouldn't mind that actually,'' Clinton said. ''The first I heard about them, I thought they were Thelma and Louise.''