Lachlan James Young, 24, took the stand in his Victorian County Court trial on Friday after pleading not guilty to a single charge of rape.
He is accused of assaulting the girl at a small house party in the Ballarat suburb of Sebastopol on February 4, 2024.
The pair met for the first time at the party and were chatting for most of the night before exchanging Snapchat details.
As the other partygoers went to bed, Young asked the teen if she "wanted to do things", the jury was told.
The girl said no because she was tired and she went to bed but they continued to send Snapchat messages to each other.
The girl told Young she was only 16 and he allegedly still asked to have sex with her, saying "just five minutes and I'll make it worth it".
The teen agreed to meet Young in the backyard and she consented to some sexual touching.
But when Young said "wanna f***", she replied "no", the jury was told.
It's alleged Young ignored the girl's refusal and instead raped the teen without wearing a condom.
Young denied the allegations in his evidence, telling jurors a completely different version of events.
He said he never messaged the girl on Snapchat to ask about her age or to organise for them to meet outside.
Instead, he told jurors he had gone to the back of the shed to urinate and the girl had followed.
The pair began kissing and touching each other and it was only then that the teen disclosed her age, Young claimed.
"Once she told me she was 16, I immediately pulled my hand out and gently pushed her away," Young said in his evidence.
"I wasn't interested in that age gap and I wasn't interested in getting into trouble."
Young told jurors he apologised to the girl and told her nothing more could happen before walking away.
Under repeated questions from prosecutor Andrew Buckland, Young denied raping the teen or doing anything sexual without her consent.
He denied he would have been aroused by the situation.
"No I had a partner at home," Young told Mr Buckland.
"I was doing the wrong thing and it shouldn't have got to this stage."
Young accepted he blocked the teen on Snapchat after she confronted him in a series of messages in February.
The jury was previously told the girl questioned how Young's girlfriend would feel about him "f***ing an underage girl and cheating on her".
"I kept receiving these messages," Young said in his evidence.
"I didn't want to entertain it as such, so I decided to block her and remove myself from the situation."
The trial before Judge Caitlin English will continue on Monday, when Mr Buckland and defence barrister Glenn Casement will give their final addresses.
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