A parade of defense witnesses took the stand in a Manassas courtroom yesterday, challenging John Wayne Bobbitt's credibility on several points, including whether he ever struck his wife in anger or told friends that he enjoyed violent, forced sex.

Testifying for the second consecutive day in his wife's trial for slicing off his penis last June, Bobbitt denied defense attorney Blair Howard's assertion that he had told others that he got excited by "hitting {women} in the behind, making them scream, making them bleed and making them crawl."

But a few hours later, two young men took the stand and directly contradicted the 26-year-old former Marine and bar bouncer. "He said he liked to make girls squirm and yell, and make 'em bleed and yell for help," said Jon Whitaker, 19, of Stafford, Va., recounting a conversation he said occurred in the fall of 1992.

The testimony came on the second day of Lorena Bobbitt's trial on a charge of malicious wounding, a case that has captured international attention because of the horrifying nature of the crime. Yesterday, jurors were shown the 12-inch, red-handled kitchen knife she used on her husband as well as several color photographs of his severed penis and resulting wound.

The jurors, seven women and five men, showed no reaction as they quickly passed the photos among themselves. Lorena Bobbitt took a deep breath and stared straight ahead.

The 24-year-old Ecuadorean-born manicurist says her attack was provoked by her husband's raping her minutes earlier. In November, John Bobbitt was acquitted of marital sexual assault in the same courthouse.

Yesterday's testimony from his friends about John Bobbitt's appetite for rough sex did not emerge at his trial, which was limited to events that occurred in the five days preceding his mutilation.

However, Lorena Bobbitt did testify then that her husband said forced sex excited him. She also made comments to police suggesting that she had struck out in anger over not being sexually satisfied.

Several psychiatrists and mental health professionals are expected to testify, starting today, that Lorena Bobbitt suffered from major depression, post-traumatic stress disorder and panic attacks.

Her defense team has portrayed her as a "classic" example of a battered wife who was sexually, physically and verbally abused throughout her four-year marriage, and maintains that the "constant and relentless violence" drove her over the edge on June 23, leaving her unable to control her actions.

If the strategy fails, she could get up to 20 years in prison on the felony charge and face deportation to Venezuela, where she grew up.

Commonwealth's Attorney Paul B. Ebert is basing his prosecution on the theory that two wrongs don't make a right -- that no matter how bad the Bobbitts' marriage had become, it didn't justify her horrific act.

Although John Bobbitt has denied ever abusing his wife, witnesses yesterday recalled seeing him strike, shove and belittle her, often for seemingly trivial matters such as how she cooked and dressed. Others told of seeing occasional bruises on Lorena Bobbitt's face and arms, or of letting her stay at their homes on nights when she called them, hysterically seeking help. Photos of a bruised and cut Lorena Bobbitt were introduced into evidence.

Hours before the mutilation, neighbor Ella Jones said, she gave Lorena Bobbitt some pamphlets on rape. Police later found them on the couple's dresser.

After severing her husband's penis, Lorena Bobbitt fled their apartment. About a half-mile from home, she realized she still had the penis in her hand and tossed it out her car window into a grassy field -- a distance of about 24 feet, according to police.

Acting on information she provided, authorities recovered the organ and rushed it to a nearby hospital, where it was reattached in more than nine hours of surgery.

One of the two doctors involved testified yesterday that when John Bobbitt arrived at the hospital, "there was nothing more than a red clot of blood left where {his} penis should have been." Holding up a photo of the severed organ, urologist James T. Sehn also said he believed that the penis had to have been "held in some tension" and the knife wielded "with some force" to make such a clean cut.

Sehn said his patient's prognosis is "quite good" although whether Bobbitt will regain full sexual function won't be known for a few years.

The doctor was one of eight witnesses for the prosecution, which rested its case at midday. Then the defense took over, calling as its first witness John Bobbitt, who, in 90 minutes on the stand, issued a string of denials. No, he never raped his wife. No, he never struck her. No, he never told his wife that her breasts were too small, although he did acknowledge teasing her that "her butt was getting too big."

He also denied pleading guilty in February 1991 to assault and battery on his wife, although Prince William County court records indicate that he did. The case was dismissed six months later after he completed counseling.

Instead, the 5-11, 190-pound Bobbitt contended that it was his 5-2, 92-pound wife who was the attacker, punching, scratching and clawing him when she got angry. "I don't believe in violence," he said he would tell her. "It's not ladylike."

"I don't have anything to hide," he said at one point, giving his wife a cold look. "Of course, Lorena does."

In his testimony, Bobbitt was able to remember small details -- what he wore on a summer day in 1989, what he had for dinner June 22 -- but had no recollection of more important events, such as meeting with a social worker at Quantico Marine Base in December 1990 after Lorena Bobbitt alleged that he tried to run her over with his car.

He also said he didn't recall filling out a form for the social worker in which he admitted several abusive acts, including throwing his wife around.

At times in his testimony, he appeared to confuse even himself, shaking his head in befuddlement.

"Mr. Bobbitt, you wouldn't want to mislead anybody with the truth, would you?" defense attorney Howard pressed him.

"No," Bobbitt responded.

And when Bobbitt said he couldn't recall an incident in 1989 in which Howard alleged that Bobbitt grabbed his wife and pushed her up against a wall, the defense attorney said, "And if anybody saw it, they're mistaken, right, Mr. Bobbitt?"

"Yes," Bobbitt said. "It didn't happen, sir."

A witness later said it did.