Wolfsburg led 3-0 in the first half, and 4-2 with less than half an hour to play at the BayArena, but required a late Dost winner to clinch the three points.
Dost took his season haul to nine but the Dutchman said he was not as taken by his own performance as he was their hosts in Leverkusen.
"Every time I scored I thought the game was over but they fought back every time. It's unbelievable," Dost told Bundesliga.com.
"If that game finishes 4-4 we'd have been incredibly frustrated but now we can laugh about it. It was a very difficult game.
"We were on top in the first half but it was a completely different story after the break.
"It was too easy for Leverkusen to get back into the game but to score five goals in an away match is great for us."
On the title race, which Bayern Munich lead by eight points to second-place Wolfsburg, Dost said he was only concerned about securing a spot in the UEFA Champions League next term.
"We're not thinking about Bayern - we're aiming for the Champions League and I'm sure we'll get there," Dost said, with Wolfsburg 10 points clear of fourth-placed Schalke.
Wolfsburg's Andre Schurrle, up against his old side, said he was disappointed with the reception he received from the home fans.
"I wasn't bothered by the reception I got from the Leverkusen fans. It was a shame but it doesn't bother me," said Schurrle, who called the BayArena home from 2011-13.
Son Heung-min, who scored a hat-trick in 10 second-half minutes, said the last-gasp concession was gutting.
"It's a big shame that we lost," the South Korea international said.
"We fought back really well in the second half and I thought we played well too, but if you concede a goal like that in the final second it's all the more painful.
