The brother of Michael Jackson's accuser offered the most explicit testimony so far at Jackson's child molestation trial.

The witness -- who's now 14 -- testified Monday that Jackson showed them Internet sex sites, gave them wine, and slept in bed with them. And he says as he and his brother were watching a movie, Jackson came into the room -- naked and sexually aroused.

The boy says he and his brother were "grossed out." He says Jackson "sat on the bed and said it was natural" -- and then left
the room.

He testified at length about alcohol -- saying Jackson referred to wine as "Jesus juice." He also testified that during a flight with Jackson, the pop star made a crank phone call to a woman in which he made remarks about genitalia.

Jackson's lawyers contend that the boys memorized security codes
and entered Jackson's wine cellar and other areas without permission. But the boy testified that Jackson was always present when they drank.