when Christians say that Jesus Christ died for your sins what it really means?

Here are a few cents about my views...

There is a belief in Christianity which states Lord Jesus Christ died for your sins.

A  believer of god must not necessarily assume that one should continue to do sin as Jesus Christ has already died for his/her/their sins.  Nor a believer should assume that he/ she is immune from the karma of sin, ( since Christianity does not talk about karma.openly)  however it actually is just a buffer time which the preacher of God ( in Christianity it is Jesus /father or son of God)  is sharing with you. 

It actually means since you have put your faith in Christ, who had died for the sin of others; 

Some one some where is dying or is likely going through hell for the sins that a believer is committing.

The statement is a wake up call, stop committing sin other wise your Jesus Christ will also just die for your sins.