You’ve conditioned yourself to love pencils of all types. You’ve had and given up several of them throughout your life, maybe hundreds. But then God comes along and gives you a new nature, that only desires one pencil. God gives you that one pencil. That fact doesn’t change that you’ve conditioned yourself to love pencils of all sorts, even ones that are not yours. Your view of pencils may even be skewed, because you have handled so many of them or they all look good, even though they are not yours.

Be warned, you may want to handle and hold those other pencils, but don’t, it won’t last, because they're not yours. Don’t stare too long at those pencils or you’ll be captured by it’s beauty (Proverbs 6:25). You may even think you can write with it for a little while, but if you did, it would destroy you and the paper it writes on (Proverbs 6:32). What if you were to get that pencil you think you really should have? Then what? It may cause you to more vividly crave other pencils, because now you have a more tangible reminder of what other pencils like it can do. It could cause you to imagine other pencils more frequently or more inappropriately. Be content with the pencil you have received, by God's grace.

Pursuing the other pencils assumes that they will satisfy you or fill the void, but it won’t, sin is deceiving. Even notice how celebrities (those with money and fame) don't usually have just one pencil. They often abandon their one pencil to use many others. And in one sense, they can have any pencil they want, yet, they demonstrate that no single pencil will ever satisfy the eyes and hands of a person that covets uncontrollably (Proverbs 27:20).

Often we have had experiences in the past with similar pencils, yet sin tells us that this other or new, yet still similar pencil will satisfy us. Sin brings deception and makes you believe the lie, but remember the truth. Namely, that simply having the pencil wasn't enough, that’s why in the past you didn't just keep one pencil, even though you only needed just one. The pencil you have is the best one, and you must condition yourself to believe what God has given you is the best pencil you should have. This must change your desire to picture or pursue other pencils that are not yours, it should make you care less or not at all about other pencils.

Like the Serpent who brought the forbidden tree to the attention of our first parents, the internet and other sinners can bring other pencils to our attention that otherwise we would not want or care about. But, now that we have been introduced to them, we develop a desire for experiencing those pencils. It is all an attempt to make us ignore or reject what God has already given us, as though it was not good enough. But, God says it is enough for us, that is why He gave it to you. He chooses better than we do. Our job is to learn to agree with God.

Keep in mind the flesh deceives, making you think having those other pencils will satisfy, they won't (Proverbs 27:20). Those other pencils may look great, but you know only the pencil God gave you is yours to have and to hold. Fight to hold on to it, by the Spirit with the word. That is wise.

When possible, you could try to righteously improve what you have, until you can’t, then assume this is the condition that God wants for it, to chisel or to mature you. It’s when we try to go beyond what God has given us, in an unrighteous way, that brings grief and misery. We are called to steward and care for what He has entrusted to us (Luke 16:10-12, 1 Peter 4:10, etc).

Know that Christ is your only escape to no longer struggle with desiring those other pencils. Long for God by His Spirit to come and remove you from the grip of these stumbling blocks. Christ sets us free from being a slave to every pencil, needing to write with them all. He changes us to love the one pencil He gave us. Which according to His wisdom, is the best pencil for you. God gives us eyes to see that those pencils are really a threat to wholeness and happiness.

Even more so, having Christ is better than having any pencil ever created, guaranteed. The gospel is better news than hearing that you got a new pencil. Why? Because eventually that pencil will get old and worn, no longer functioning the same. Whereas, Christ is the same forever, therefore beautiful and glorious forever (Hebrews 13:8). He is greater, hold fast to Him; not to forbidden pencils (Proverbs 5:20, 22:14). Soli Deo gloria

Other things to think about:

1. Coveting attempts to redirect our attraction or joy away from the things God gave you and move them to the things He has not given you. It’s akin to stealing.
2. We must be content, train yourself to be content with what God has given you. You must find ways to be content/satisfied with what God has given you. Focus on what you do like or enjoy about what you currently possess. If you can't find anything, then remember God still gave it to you, so enjoy the fact that God saw fit in His wisdom to give you what you have now, for His reasons. He knows better than you.
3. By default we pursue happiness and full contentment apart from Christ. And it always fails, then leaves us wanting more. A person can have the most gorgeous spouse, but still commit adultery with someone else. God is only able to bring us full happiness that won’t wear out. We must learn to be satisfied with what God gives us, knowing that everlasting happiness will come only in glorification. You want it just for earth or for eternity?
4. God has made things to look good, its appropriate to acknowledge that God gives good things to others as well. But, not all good things are your things. For example, I can give a gift to one of my children and tell the others not to play with it. They should obey, even though the gift is a good thing that will be desired, which is why I bought it and gave it. But, that doesn’t mean anyone else can take it as their own without negative consequences.
5. Coveting is one of the only sins an Apostle of Christ admitted to struggle with (Romans 7), it should be no surprise you struggle with it as well. Fight by the power of Christ to put it to death, not by the flesh.

Related article: Being Satisfied with Christ