Amber Heard Describes First Time Johnny Depp Allegedly Hit Her

2:21 PM PT -- Amber says once on a flight to Russia, she and Johnny decided to take MDMA and Johnny convinced a female flight attendant to do the same. Amber says the flight attendant became comfortable with her, touching her, which pissed Johnny off.

Amber claims Johnny then slammed the attendant's wrist on a table, telling her not to touch Amber. Amber says the whole thing triggered memories from her own experiences with Depp.

1:36 PM PT -- Amber just detailed the time Johnny allegedly searched her entire body for drugs ... and it got emotional.

She described the incident as a cavity search, saying Johnny poked around the inside of her vagina looking for cocaine he believed she was hiding from him. Amber said she would never hide cocaine in her body, because she didn't like drugs.

Amber told the jury the alleged incident went down on a group getaway to Hicksville Trailer Palace in Joshua Tree, CA ... and she says Johnny did the alleged cavity search in one of the trailers, even ripping one of her favorite dresses in the process.

She says she just stood there staring at a light in the trailer and didn't tell him to stop.

Also during her testimony, Amber recalled an incident where Johnny allegedly grabbed a teacup Yorkie while they were driving and held the pooch out the window of the moving car and started howling.

12:16 PM PT -- Amber just described the first time Johnny Depp allegedly hit her ... and it was tearful testimony. Unclear what year this supposedly happened, but she says they were on a couch and that he was drinking -- on top of that, she says she also believed he'd been using coke ... based on a jar of the stuff she claims was on the table nearby.

She goes on to explain that she asked him about a tattoo on his arm, and he said it read "Wino," which Amber says made her laugh because she thought he was joking. Suddenly, she claims he slapped her across the face -- which left her stunned. She testifies that he slapped her a second and third time as well, allegedly saying ... "You think you're a funny bitch?" Amber says she hoped and prayed he was gonna say "kidding" at some point.

When that didn't happen and she realized he was dead serious, she says she started to leave -- which made him start to bawl and apologize. She says he was on his knees asking for forgiveness, explaining that he thought he'd "put the f***er away," referencing a "monster."

She says she left the house, but that they spoke privately later ... where he vowed he'd never hit her again -- so she stayed with him. From there, she says things became violent between them regularly ... claiming Johnny would often drop in on her and accuse her of infidelity ... and often strike her during fights, despite her denying his accusations.

11:49 AM PT -- Amber's describing how Johnny came on strong when they filmed 'The Rum Diary,' saying he was the one who kissed her first. Once they circled back a couple years later for the press tour -- she says they embarked on a whirlwind romance that was hot and heavy ... and for which she says she was head over heels at first in the early stages of their relationship.

She references a "bubble" in which they dated -- apparently they were together in secret at the time -- and Amber says she was overwhelmed with the lavish gifts and worldwide destinations he invited her to see with him. Basically, things were great in the beginning.

11:23 AM PT -- Amber's first words under oath were emotional ones -- her lead attorney asked what she made about the fact that she was here in court over this matter ... and AH held back tears as she described how horrifying and painful it was for her to relive this chapter of her life.

Sounds like she's upset about the fact that some people she knew back then have spoken ill of her ... getting into the details of a private life she shared with then-husband, Johnny. Amber also briefly spoke about the U.K. trial a bit -- noting she was the star witness there ... and hates that she's having to go through this all over again on the biggest of stages.

So far, she's going through her early life and explaining how she landed in L.A. ... going through the same sorts of beats and motions that Johnny did, at first, when he testified. Amber is also recounting how she first encountered Johnny during "The Rum Diary."