Moose Dupont, the Philadelphia Flyers' pugnacious defenseman, is a man of few words. He was a player of minuscule ability, too, until Flyer Coach Fred Shero, then at Omaha of the Central Hockey League, pointed out some of the subtler aspects of the game.

"When you make a mistake," Dupont said, "he explains what you did wrong instead of getting on you about it. Everything I know about hockey, I learner from him."

Well, almost everything. Yesterday, Shero, watching films of Sunday's 3-1 victory over the Boston Bruins, suddenly erupted at a repeat viewing of Dupont's post-goal dance.

"Why the hell does he have to do that?" Shero asked. "That's one thing I can't stand in sports. I believe our sport can sell itself without this nonsense. Football's just as bad. What would baseketball do if the players danced a jig after every basket?"

Frequently, a kidder, Shero was serious this time. He has often stated that he never sent a player on the ice deliberately to incite violence, but after his criticism of Dupont's pirouettes, he conceded there had been at least two occasions with malice afore-thought.

"That center for the Islanders, (Jude) Drouin, he always used to dance around after he scored," Shero said. "I told my guys if he ever did it again, to nail him. He scored and started carrying on and he got sent sailing into the boards. That ended that.

"When I was in Omaha, there was a guy who used to skate a full circle, at least five times, out around the blue line everytime he scored. I told one of our guys to drop a glove and bend over, then reach up and belt him. About the third circle, after he scored, my guy laid him out. He didn't pull that anymore."

Shero blames television for encouraging players to exaggerate certain aspects of the game.

"Before TV if somebody got hit, you'd just drag him off the ice and get play going," Shero said. "Now they're out there, rolling and moaning like it's their last breath."

Since joining the Flyers in June 1971, Shero has won two Stanley Cups, posted a remarkable .641 winning percentage in the regular season and won games at a 592 clip in the playoffs. He has lectured in Russia and earned accolades as one of the sport's great tacticians. He has also been labeled "Freddie the Fog" for some of his incomprehensible replies to questions.

Shero admitted yesterday that he is unwilling to tell all to the press, during a discussion of Tom Bladon, the Flyer defenseman who has become a target for Spectrum boo birds because of some sloppy puck handling.

"If it wasn't for Tommy," Shero said, "we wouldn't have won two Stanley Cups. I keeep playing him when people are booing because he's the best man I have for the job. If a coach listens to the fans, he's got to be goofy.

"Tommy has made some mistakes, which I've pointed out to him. People don't make mistakes because they want to. Tommy is pressing and I know why, but I can't tell you. I'd be telling the opposition something. I'm not going to help them out anymore than they'll help me out. There are two guys on the Boston team hurting, because they're not playing the way they should, but Boston won't tell you about it.

"Years ago I had a good skating winger playing for me and I wanted him to play on both sides. He did an excellent job on the right wing, but he flatly told me he couldn't play the left side, no matter how much I badgered him. It turned out he couldn't see out of his right eye. He was gone the next year - he's coaching in Europe now - but I never told anybody."

Shero will use just about any psychological ploy to win, and he is not upset by others' words. Boston Coach Don Cherry accused Shero and the Flyers of "whining" about their two losses in Boston, but Shero declined to counterattack.

"Everybody uses different ways to get his own team up," Shero said. "Lots of times we call each other names, but we don't really mean it. If the coaches aren't for each other, who is? We're the only people for each other and we'd better be for each other."

Shero did accuse the Bruins of some smutty tactics in the past, a charge confirmed by the Flyers' Ross Lonsberry, a former Boston farmhand.

"I'll never stoop to what the Bruins' organization did to Omaha when they were playing their Oke City club," Shero said. "They sent six broads over to our hotel and they raised so much hell we never won another game."

While Montreal seeks a semifinal sweep in pacified Toronto tonight, the Bruins and Flyers contest game four of what seems a war of attrition, one that Shero expects to escalate into violence at any moment.

"The longer this series goes, there has to be a blow up," Shero said. "It won't come from the tough guys, but probably from some little guy who says he's had enough. If there isn't a blowup between teams like these, in a series like this, then somebody isn't trying."