Bashir was chosen for the tour of India despite playing only six previous first-class matches and picked up two five-wicket hauls in three matches.
Still behind Leach in the Somerset pecking order, Bashir went on loan to Worcestershire earlier this summer in order to play in the County Championship.
When he made his England home debut in the first Test at Lord’s he was not required to bowl as West Indies were beaten in straightforward fashion.
He bowled in a home Test for the first time in Nottingham and became the first spinner to take a five-wicket haul at Trent Bridge since 2006.
And Bashir said Leach told him to “enjoy” the experience.
“A home crowd, it doesn’t get better than that,” added Bashir. “It’s just so special to make a home debut.”
Despite a modest domestic record – Bashir averages 77 with the ball in the County Championship this summer – England have identified him as a Test bowler because of his skills and attributes.
At 6ft 4ins he is unusually tall for a spinner and his release point of 2.35m is the third-highest recorded for a slow bowler in Test cricket. England believe this can be particular weapon on the hard, bouncy pitches of Australia on the Ashes tour of 2025-26.
“I’m grateful I’m a 6ft 4in spinner because it’s a nice attribute to have,” said Bashir. “If you land the ball in the right areas, a few will bounce and a few will skid on, so the bounce does help.
“It’s always a learning curve. I’m grateful for everything that’s been given to me and I’ve just got to keep working hard. I’m still learning, still developing.”
England hold an unassailable 2-0 lead over West Indies and will aim for a 3-0 clean sweep in the third Test at Edgbaston, which begins on Friday.