"on the first session" is a correct and usable phrase in written English.
You can use it whenever you are referring to the initial meeting or encounter with someone. For example: "The two leaders discussed their differences in detail on the first session of negotiations."
My take on the first session?
Mining companies led the way, with their shares jumping in quiet trading, on the first session since the Christmas holidays.
Three years later, aged 20, Emerick was promoted to engineer on the first session for the band's album Revolver.
Data from 9 additional participants were excluded due to performing lower than 2 SD below average on the first session test (2 subjects) and procedural difficulties (7 subjects).
Gazing at a television while overlooking Weymouth Bay, where he had gone to watch sailing's Ben Ainslie with the IOC president, Jacques Rogge, he saw a packed Olympic Stadium roaring its approval on the first session of athletics.
Data from 11 additional subjects were excluded due to: napping for less than 20 min (3 subjects), falling asleep during the quiet wake period (7 subjects), and performing lower than 2 SD below average on the first session test (1 subject).
I am Scott Heinrich, your company for the first session on day two at Centurion.
On July 19 the first session of the Great Hural elected a new speaker, Lhamsurengiyn Enebish, secretary-general of the MPRP.
Shares of Kraft fell approximately 2% on Monday, the first session since Kraft became an independent company.
The mean gray matter CBF was 46.6±7.2 mL/min/100 g on the first sessions and there was a significant decrease of 9.8% between first and second session (p=0.027).
Exploring the family context and the personal desires on the first sessions could help the women to know the possibilities for them of building a family.
