West Brom won 1-0 on the night at the Hawthorns to level the tie at 2-2 on aggregate thanks to Craig Dawson's first-half header.
"We practise penalties, so I think I must've faced a 100 a day the last few days."
Conor Hourihane, Mile Jedinak, Jack Grealish and Tammy Abraham kept their cool from the spot as Villa set up a May 27 Wembley meeting with Leeds or Derby for a lucrative place in the Premier League.
Marcelo Bielsa's Leeds hold a 1-0 first-leg lead over Frank Lampard's Rams ahead of the second leg at Elland Road on Wednesday.
Villa missed out in the playoff final last year, losing 1-0 to Fulham and Grealish, who has been linked with a summer move to Tottenham, is keen to make amends in what could be his final game for the club.
"The crowd made it tough with the atmosphere but in the end I felt we ran out worthy winners," said the midfielder.
"It's no good getting to Wembley and falling at the final hurdle again, so fingers crossed. All of us are very hungry.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)