It had been a few weeks since Peter had accepted his parents' offer.

He and the team were eating breakfast in the dining room. Sam and Clint were arguing like no tomorrow. Bruce and Tony were discussing the lab. Cap and Bucky were talking about cooking, every so often glancing back at Peter. Wanda and Pietro were talking with Peter. The Twins had become like siblings to the young assassin in the weeks they had known each other. Natasha just watched on fondly.

The family walked to the training room, ready to train Peter. Natasha set up a training dummy and turned to her son. 

"The objective is to knock it out, not kill it. Ready?" Natasha asked. Peter nodded and began to train. Peter fought it, but eventually he made a mistake. He plunged a knife into the dummy's chest. The dummy turned red before shutting off. Peter's eyes flashed with fear once he realized what he did.
"I'm sorry, I'm sorry! i know i messed up!" Peter said, eyes wide. Bucky walked over to Peter, cautious. 
"Hey Bud, it's okay. People make mistakes." Bucky assured his son. Peter shook his head, hands over his eyes.
"I failed- I failed." Peter muttered, rocking back and forth on his heels. Natasha came over and guided the now crying boy to a bench. She helped him sit down and began to sing to him quietly. Slowly, Peter opened his eyes and leaned onto his mother's shoulder.
"W-what was it like to leave me behind?' Peter asked quietly. His parents' hearts broke.
"О, детка, мне очень жаль. Я люблю тебя, я никогда не хотел оставлять тебя там. Ты всегда будешь моим маленьким пауком.(Oh baby! I'm really sorry! I love you, I never wanted to leave you there. You will always be My Little Spider.)" Natasha whispered to her son.
It took a few weeks, but eventually Peter got better. He got used to the ways of the Avengers, and even became his own vigilante, Spider-Man.