MANILA (UPDATE) - Davao City Vice Mayor Paolo Duterte's legal counsel on Thursday questioned Senator Antonio Trillanes IV's motives for asking the President's son to show his back tattoo at a public hearing.

"Why does he want to see my client's tattoo? Is he gay? If he's gay, I may have allowed him to see it," lawyer Rainier Madrid told reporters after his client attended the Senate Blue Ribbon Committee hearing on the entry of a P6.4-billion shabu shipment that has exposed alleged corruption at the Bureau of Customs (BOC).

Madrid said he advised Duterte to decline Trillanes' request as the body mark was not related to the subject of the nearly 4-hour hearing.

Trillanes had asked Duterte to show his back tattoo as this would purportedly prove that he is part of the triad, an international crime syndicate.

"My client refuses to be an "uto-uto" (gullible)... I will not allow my client to be humiliated under such a silly circumstance," Madrid said.

"We do not want to dignify Trillanes' accusations and fishing expedition. The issue discussed in the committee is not [the] existence of the tattoo," he added.

Madrid said he neither saw nor confirmed from the Vice Mayor if the tattoo on his back was a "colored dragon" as Trillanes had alleged.

"A tattoo is a very private matter. I won't ask my client to show it to me unless I'm gay and I want to see his body," he said.

"A tattoo is a fad, even celebrities from Hollywood have it... He was good enough to admit he has a tattoo because he was a young lad na nadadala sa uso-uso. But to say that he is a member of a triad is too much."

Madrid said Trillanes was just spewing propaganda to get back at President Rodrigo Duterte for not choosing the former soldier as his running mate in the 2016 presidential elections, where the Senator had lost his bid for the vice presidency.

"He's just going after the President's weakest link, which is his son," he said.

During the Senate Blue Ribbon Committee's seventh hearing on the Customs corruption mess, Trillanes alleged that the Vice Mayor belongs to a "triad" behind smuggling activities in Hong Kong and China.

The senator said proof of Duterte's triad membership was a "colored dragon tattoo" on his back that had serial numbers that would indicate which "triad faction" he belonged to.

But Duterte refused to show the body mark, invoking his right to privacy.