diff --git a/contracts/NonfungiblePositionManagerV4.sol b/contracts/NonfungiblePositionManagerV4.sol
index 587beb43..c23464bf 100644
--- a/contracts/NonfungiblePositionManagerV4.sol
+++ b/contracts/NonfungiblePositionManagerV4.sol
@@ -6,7 +6,7 @@ import {ERC721} from "@openzeppelin/contracts/token/ERC721/ERC721.sol";
 import {IERC721} from "@openzeppelin/contracts/token/ERC721/IERC721.sol";
 import {PoolKey} from "@uniswap/v4-core/contracts/types/PoolKey.sol";
 import {IPoolManager, PoolManager} from "@uniswap/v4-core/contracts/PoolManager.sol";
-import {Currency} from "@uniswap/v4-core/contracts/types/Currency.sol";
+import {Currency, CurrencyLibrary} from "@uniswap/v4-core/contracts/types/Currency.sol";
 import {BalanceDelta} from "@uniswap/v4-core/contracts/types/BalanceDelta.sol";
 import {TickMath} from "@uniswap/v4-core/contracts/libraries/TickMath.sol";
 import {PoolId, PoolIdLibrary} from "@uniswap/v4-core/contracts/types/PoolId.sol";
@@ -27,6 +27,7 @@ contract NonfungiblePositionManagerV4 is
     Multicall
 {
     using PoolIdLibrary for PoolKey;
+    using CurrencyLibrary for Currency;
 
     IPoolManager public immutable poolManager;
 
@@ -124,8 +125,32 @@ contract NonfungiblePositionManagerV4 is
         );
     }
 
+    function settleDeltas(address from, PoolKey memory poolKey, BalanceDelta delta) internal {
+        if (delta.amount0() > 0) {
+            pay(poolKey.currency0, from, address(poolManager), uint256(int256(delta.amount0())));
+            poolManager.settle(poolKey.currency0);
+        } else if (delta.amount0() < 0) {
+            poolManager.take(poolKey.currency0, address(this), uint128(-delta.amount0()));
+        }
+
+        if (delta.amount1() > 0) {
+            pay(poolKey.currency0, from, address(poolManager), uint256(int256(delta.amount1())));
+            poolManager.settle(poolKey.currency1);
+        } else if (delta.amount1() < 0) {
+            poolManager.take(poolKey.currency1, address(this), uint128(-delta.amount1()));
+        }
+    }
+
     function lockAcquired(bytes calldata rawData) external returns (bytes memory) {
-        // TODO: implement this
+        require(msg.sender == address(poolManager));
+
+        CallbackData memory data = abi.decode(rawData, (CallbackData));
+        if (data.callbackAction == CallbackAction.Mint) {
+            MintParams memory params = abi.decode(data.params, (MintParams));
+            (uint256 tokenId, uint128 liquidity, BalanceDelta delta) = mintCallback(params);
+            settleDeltas(data.sender, params.poolKey, delta);
+            return abi.encode(tokenId, liquidity, delta.amount0(), delta.amount1());
+        }
     }
 
     /// @inheritdoc INonfungiblePositionManagerV4
@@ -144,7 +169,29 @@ contract NonfungiblePositionManagerV4 is
         checkDeadline(params.deadline)
         returns (uint256 tokenId, uint128 liquidity, uint256 amount0, uint256 amount1)
     {
-        poolManager.lock(abi.encode(CallbackData(CallbackAction.Mint, msg.sender, abi.encode(params))));
+        (tokenId, liquidity, amount0, amount1) =
+            poolManager.lock(abi.encode(CallbackData(CallbackAction.Mint, msg.sender, abi.encode(params))));
+    }
+
+    function mintCallback(MintParams calldata params)
+        internal
+        returns (uint256 tokenId, uint128 liquidity, BalanceDelta delta)
+    {
+        PoolId poolId = params.poolKey.toId();
+        (liquidity, delta) = addLiquidity(
+            AddLiquidityParams({
+                poolKey: params.poolKey,
+                tickLower: params.tickLower,
+                tickUpper: params.tickUpper,
+                amount0Desired: params.amount0Desired,
+                amount1Desired: params.amount1Desired,
+                amount0Min: params.amount0Min,
+                amount1Min: params.amount1Min
+            })
+        );
+
+        tokenId = _nextId++;
+        _mint(tokenId);
     }
 
     modifier isAuthorizedForToken(uint256 tokenId) {
@@ -235,7 +282,7 @@ contract NonfungiblePositionManagerV4 is
     }
 
     /// @notice Add liquidity to an initialized pool
-    function _addLiquidity(AddLiquidityParams memory params) internal returns (uint128 liquidity, BalanceDelta delta) {
+    function addLiquidity(AddLiquidityParams memory params) internal returns (uint128 liquidity, BalanceDelta delta) {
         (uint160 sqrtPriceX96,,,) = poolManager.getSlot0(params.poolKey.toId());
         uint160 sqrtRatioAX96 = TickMath.getSqrtRatioAtTick(params.tickLower);
         uint160 sqrtRatioBX96 = TickMath.getSqrtRatioAtTick(params.tickUpper);