The 21-year-old joined Pompey ahead of the loan deadline and made his debut from the bench at the weekend as the club ended a run of seven consecutive league defeats with a 1-1 draw at Coventry.
Pompey's equaliser came in stoppage-time, and now Jervis - who has already had loan spells at Carlisle and Tranmere this campaign - wants the club to push on when they return to action on December 8.
"It's been difficult for me moving to different clubs on loan this season, but I've scored goals wherever I've been," he told Portsmouth's official website.
"This club didn't need any selling to me - it's huge. To come here, help the cause and help fire Pompey up the table is a big incentive.
"It would be better if we had another game straight away so we could keep the momentum going, but the break gives us time to work together as a team."