After last week's 2-2 draw in Germany, Bayern will have to beat Real in their own back yard if they are to reach the final at Wembley.
With Bayer Leverkusen ending Bayern's 11-year Bundesliga reign by securing the league title last month, the six-times European Cup winners have only one trophy left to fight for this season.
Tuchel spent several minutes talking to his players in an empty Santiago Bernabeu stadium on Tuesday and said that he told them they needed to find extra motivation within themselves.
"It is important to connect with your own inner child. When we were little we played these games in the garden. So now we are here and that's our chance to make it true," he told a press conference in Madrid.
"I think both teams have to endure defending and suffering when their opponents have the ball. It is extremely difficult to steal the ball from Real Madrid. Both teams are very, very strong in the transition game. It gets very complex. You need luck and precision. Then everything is possible at this stage."
Bayern were undone by a clinical Real in the first leg, with the German side dominating for large periods without putting their opponents to the sword.
Two goals from Real's Vinicius Junior either side of efforts from Leroy Sane and Harry Kane left the tie poised on a knife edge, but with Real favourites to advance with the second leg in Spain.
Real, the record 14 times winners, have an aura in the Champions League, but Tuchel said the Spaniards' record holds no fear for his side.
"Bayern are also one of the most successful and dominant clubs in the world and we have an obligation to do our best when we step on the pitch tomorrow," he said.
"You don't talk about myths, that would make it harder for us. It is already one of the toughest stadiums to win but not impossible. We are not here to enjoy the moment."
Bayern reached the Champions League's last four for the first time since winning the competition in 2020, while Madrid last lifted the trophy in 2022 with an amazing run of comeback wins at home to reach the final.
Real are bidding to win their sixth Champions League title in 10 years having clinched a record-extending 36th LaLiga crown on Saturday.
The Bavarians, however, have endured a disappointing domestic run and Tuchel will exit at the end of the season.
"Real Madrid are an amazing team but we need to be confident in ourselves and help each other, we can't be stuck or afraid. We need to make something positive from the pressure," Bayern goalkeeper Manuel Neuer said.
"Against a team like Real Madrid, it's the little things that matter. Nobody wants to make a mistake because both teams have very good offensive power."